Thunderbolt 5 is USB 4. No need for a new USB 5. Those Thunderbolt 5 speeds are already part of the USB 4 v2 spec, which actually came out 3 years ago back in 2022.
You are missing the point that something 'next gen' is a major contributor to the current gen being pushed into the default platform at the lower levels. The issue here is why does the iPad Air need super duper I/O. It doesn't .
The more mature tech is always going to be cheaper to implement and when get to the lower end of the line up where costs matter more.
If there is no USB 4 v3 , v4 etc. spec there is little chance for there to b e a Thunderbolt follow on. Thunderbolt is a "less optional stuff than USB" type of spec at this point. Intel was a major ( and probably critical) factor and pushing USB 4 v2 through. If Intel isn't pushing new stuff, then who will? Apple trying to do it all by themselves. Apple doesn't have the leverage with the committee. Intel being a dominate almost monopoly player is important piece of the puzzle of progress.
The USB is spec is primarily built so to make it easier to stick to the minimal cost option as your standard for base offerings. ( e.g., minimal required speed for Type-C connectors is USB 2.0 . that allows implementors to spend about as little money as they want. ).
AMD and Qualcomm are far more likely to fall in behind pushing more Oculink provisioning than Thunderbolt-like alternative. It is cheaper.
I suspect Intel will survive as a significant play in 3-4 years, but until then they have got lots of internal problems that leaves little time, money , and resources to be fighting USB committee on progress they generally don't want to make. Apple has distractions in Vision/Glasses custom chips for those. Making their modem line work long term, and even getting Ultra chips on a regular basis that doesn't loose money.
Also, Panther Lake is essentially a soon-to-be-current 2025 chip, not a far-into-the-future chip. Furthermore, cheap third party Chinese discrete chipsets for USB 4 v2 should be out by 2027.
cheaper discrete chipset is all the more likely that this won't make it to the base Platform chiplet. If Intel was the overwhelming dominate player perhaps that would trigger a platform tile inclusion, but they aren't any more. Intel has been in trouble for years. This three way split of the basic CPU package is more expensive than what AMD, Qualcomm, MediaTek/Nvidia are doing. There is still going to be cost pressures to keep the Platform chiplet cheaper in Nova Lake also. ( Intel killing off rentable units and having to throw more money at the CPU chiplet redesign only makes cost control worse. )
For Macs, I was talking about Apple integrating Thunderbolt 5 in say M7 Macs or later, several years from now. Regardless of what Intel does, Apple already incorporates TB 5 into its mid-range and upper chips now, so it's a not a big stretch to think they'll also incorporate TB 5 into its base chips several years from now.
Apple kept FW800 segregated on the 'upper half' units right up until the end. The increasing horsepower that Apple is putting into the base level units has more folks moving down in the product line up ( because it is fast enough). Segregating on I/O will partially offset that. Apple isn't going to be in trouble if folks spend $400 more to get the higher end I/O.
As for going beyond DisplayPort 1.2, it seems DP 1.4 is already very common with the vast majority of mid and upper range monitors supporting DP 1.4 (and some supporting DP 2.1),
Sorry that was a digit flip typo. It should have been 2.1. Apple doing a 2.1 pass through doesn't require much in terms of additional switch complexity work. It is also less asymmetric bandwidth pressure on the internal SoC data bus from Display Processors to the TB controllers.
and Apple's base Macs already all start with at least DP 1.4. Basically, all I want... several years from now... is all base Macs to have DP 2.1. (I'm not counting the rumoured future Ax series MacBooks.)
The base ones getting DP 2.1 passthrough wouldn't necessarily mean they were getting TBv5.
In case you're wondering why it matters to me... It's for ultra high resolution monitor compatibility. On paper it really shouldn't matter, since it's very unlikely I will be moving beyond 6K monitors anytime soon, and 6K 10-bit 4:4:4 60 Hz is already supported on DP 1.4 (but not DP 1.2). However, to implement 6K 10-bit 4:4:4 60 Hz on DP 1.4 requires DSC. That's fine, but there are a few buggy implementations out there that screw up DSC compatibility, meaning that some of these new non-Apple 6K monitors drop down to 4:2:2 chroma at 6K 60 Hz on Macs. Having DP 2.1 removes the requirement for DSC, and removes that source of compatibility issues.
so yeah DP v2.1 pass through would solve the problem. Non buggy DSC from Apple would help even more.
I think the 'tag wags the dog' pops up where next gen Pro XDR has to have TBv5 so therefore Apple has to rollout out TBv5 to iPads so that they can run $5,000 monitors at max refresh rates. ( versus folks who buy $5000 monitors just buy a $500 more expensive Mac. )
That said, if say by the time I really want to upgrade several years down the line, I'll still have the option of getting an Mx Pro, which already incorporates TB 5 / DP 2.1. Also, HDMI 2.1 is already on current Mac minis, and that also supports 6K 10-bit 4:4:4 60 Hz without DSC, albeit without the bonus of Thunderbolt 4 and USB 4 peripheral support.
I would expect provisioning backhault to HDMI 2.2 out of Apple on the base level chip support before TBv5. By M7 era that would be more common on TV's of that era than trying to do upmarket >= 6K stuff.