Since the M1 is the only SoC option available, that is not surprising.
I have not been able to watch the keynote, but from what little I have seen, the M1 is an A14X with additional hardware specific to the Mac / USB4 / TB3. It's clear it only has a single USB/TB controller so not surprising it is limited to two ports at the moment. I also think the 16GB limit might be either the memory controller or just the available space they had on the die.
Since the A14X hasn't been shown the position that this is "extra Mac only" hardware really isn't grounded.
The current iPad Pro comes with a USB-C socket. It connects to a keyboard that also provides a separate USB-C data line feed from the socket on iPad Pro. So two.
If Apple drops a "A14X" into a new iPad Pro then it will be USB something. It seriously would not be hard for that to be USB 4. The A12Z in the current iPad Pro is over two years old at this point ( basically it is a A12X).
If Apple doesn't want Thunderbolt drivers mixed in with iPad OS then they can nominally just ignore the Thunderbolt part .... and it would still technically qualify as officially USB 4. If Apple did their own custom TB controller so they could lock it down hard enough for iPad OS usage then IPad Pro's with Thunderbolt would be a decent feature differentiator from the mainstream iPad ( which is getting FaceID , etc ... that contributed differentiator. )
If the USB 3.2 2x2 was some annoying power draw ... again it is their own TB+USB 3.x controller. So they can just flip off the the higher power mode on iPad Pro. At that point they'd loose the USB 4 badge but still could do it with same controller. (but again does Apple really want to walk the iPad Pro back to the iPad Air. ) .
They could also just provision the iPad Pro with just less memory. 6GB instead of 8GB. Don't need a new memory controller for that .
An article over at Anandtech did some back of the envelope on the size of the M1 ....
"...If Apple was able to keep the transistor density between the two chips similar, we should expect a die size of around 120mm². This would be considerably smaller than past generation of Intel chips inside of Apple's MacBooks.... "
Seeking answers? Join the AnandTech community: where nearly half-a-million members share solutions and discuss the latest tech.
www.anandtech.com
The A12X size ??
" ...This is approximately 45% more than the 6.9 billion of the A12. In terms of silicon the die, it will likely be around 120 mm2,
based on the A12’s 83 mm2 and the same 7 nm process. The “X” variant is, once again, sporting a good sized piece of silicon. ..."
As predicted, Apple introduced a new processor at its Oct. 30 event. Here's what we learned about it.
www.eetimes.com
the 16GB limit probably more to do with limiting to just two DRAM packages and the max memory density can get out of those (at price points Apple wants to pay). The memory controller is probably tunes to that, but that "two package" limit is probably the constraint. Two chip limit... same as iPad Pro.
From 11" teardown (step 8)
The new iPad Pro 11” sports narrower bezels, curvy LCD corners, and cutting edge silicon. This is apparently the iPad Apple dreamed about building...
www.ifixit.com
Yellow box above. Two DRAM packages.
Walks like a duck , quacks like a duck .... probably a duck.
If the 14X dramatically shrinks in size then the iPad Pro is on a different development track. Time will tell.
But the highly established track record of the Apple Slicon solutions is for them to be reused in multiple products.
The 14X 'mode' would probably have a different power threshold curve, but a whole different chip optimization? Probably not. If there was a silicon gap then they might shrink the L2 caches back to the A14 size levels, but I doubt that is really "buying" a whole lot that isn't offset by economies of scale of doing more uniform larger volume batches. The winked out only 7 GPU cores M1s in the entry MBA . Pretty good chance that is where the A14X is aligned with. ( Apple could just wink out 1-2 GPU and/or 1-2 Performance CPU cores ) and slap a different label on it.
The Intel MacBook Air only has two TB ports and the old non-Touchbar MacBook Pro 13 also only has two ports. So the M1 is meeting that and it's $100 cheaper than the base Intel model so you could argue that is to reflect losing those two ports.
Once even up the M1 MBA to 8 GPU cores and match up the SSD level the price to MBP 13". The price the same.
The "touch bar" haters can buy the MBA. The folks don't mind the "touch bar" can get the MBP 13".
Those two are almost the same system. ( Better thermal curve probably on MBP 13" and 100 nits of brightness on MBP 13' but that is probably lost on most users. ).
The "butterfly keyboard" dustup eclipsed the backlash on the "touch bar" , but the two laptops are pretty close to the same model just with "user selected" option out/into the "touch bar".
The Mini also has major problems compared with WinPC desktops as the price range goes up. Ryzen 7 5800X paired with a modest discrete GPU and the Mini isn't going to look like some kind of "Performance King" anymore of a wide variety of workloads. ( yeah it is smaller , but faster starts to slip away. ) . Apple is a bit luckly that AMD bumped the Ryzen 7 5000 prices up a bit.
As for the M1 Mac Mini, I see this as the model for software developers (who don't want to use an M-series laptop) and for folks who use their Mac Mini as a home media server or such. So the RAM and I/O restrictions are not crippling and you pay less.
An M1 Mac Mini as a media server is just gross overkill. I'm sure there is some fringe that will do it . There are probably more units allocated to cloud services ( LAN and remote : virtual machine hosting , on demand "test and build" systems, etc. )
A mini is going to help more revised software get out there faster as some major development build chains use them. ( that is why the DTK form factor made sense also. )
The RAM constraint will hit folks with substantive concurrent virtual machines images running. Apple is throwing other minor roadblocks are virtual machine hosting but that cap is going to limit things.
The cheaper helps in that it will probably encourage more exploring by more groups of whether they want to make the move. Also going to be some folks engaged if the iMacs take longer than folks are expecting.
The next model of ASi SoC (M1X / M2) will likely offer more cores (CPU and GPU), a higher unified memory limit (32GB+) and will have additional controllers for more USB/TB ports. That is the SoC I expect to go into the 14" and 16" MacBook Pros and they will have four ports.
Adding another TB controller isn't going to help if still stuck with just two DisplayPort streams. The GPU subsystem will nee substantive improvements too. At least one more DP output stream.