I have two Samsung tablets (S8 Ultra nd S9 Ultra) and a phone (Z Fold 4) with DeX and it sucks, especially when trying to use my fingers for navigation. Windows appearing all over the place isn't good if you don't have a mouse. Things get overlapped and inaccessible unless I have a mouse. I'm fully convinced Samsung created DeX to make phone apps look better because then they'd be all stretched out and awful looking since tablet-optimized apps on Android are few and far between. I find nothing useful about DeX, and I love my Galaxy tablets for being good tablets, not for being bad laptops. There's a reason Apple doesn't have that mode. It absolutely requires a mouse and Apple is touch-first, which makes it still the best tablet. Even Apple requires touch-first on Stage Manager unless it's on an external monitor (obviously since there's no touch screen on a monitor).
I almost included something more about Samsung in my last post, but it was getting a bit long. I was going to say that Samsung's Dex seems like a cool but not very useful proof of concept. They have the willingness to try stuff out like this, and it's nice to see a tablet transform into a desktop experience, but as you say there is very little software support, and while it looks like a desktop UI when you don't look too closely, it doesn't come close to what Apple or Microsoft could do if they chose to go down this path.
But I don't see any issue with it being pretty much dependent on mouse and keyboard, as that's what it's for isn't it? You have the touch first tablet interface when you want that, and the mouse and keyboard first interface when you want that.
I bring both my iPad and MacBook Pro 14" when I travel, but that's because I play World of Warcraft on the laptop and can't on the iPad. I'm fine with that. I wouldn't want it to run on the iPad because my iPad would burn up if Blizzard were foolish enough to make an iPad version. WoW can actually test the fans on a MacBook (it gets really loud and hot, just like a Windows PC), and I would hesitate trying to run the game on a MacBook Air, fearing my frame rates would drop to unplayable when it throttles. Some things are better left to a Mac while other things are best left to an iPad, and that's just fine. That's exactly why Apple sells four lines of computing devices in ascending order of power: iPhones, iPads, Mac laptops, and Mac desktops. The SoC isn't everything. It's thermals, form factor, and user interface that goes along with the SoC.
This one I am not so sure of. I've heard that people are able to get a solid 60fps in WoW on an Air, and while the iPad certainly has less thermal capacity, it a) won't go beyond its thermal limits, and b) the performance when fully throttled is still decent for what it is. I think WoW would be doable on the iPad, but concede that it's just a guess on my part.
When you can outperform a Steam Deck with the thin and light passively cooled M1 iPad, it is something special and far more could be done on it than is being done on it.
Some day, there may be revolutionary changes in battery technology along with chips so power efficient and fast that this may end up being a reality. Of course, the problem with the latter is that software has this tendency to eat up any performance gains hardware makes, so that problem may never go away. For now, it's not happening. Apple does tell us they're forever experimenting in their labs, but the fact that they don't do it tells you something. They are all about the user experience, and getting that 100% overlap won't happen anytime soon. Maybe not in my lifetime (I'm older than most on this site).
We do seem to be approaching a sweet spot with passively cooled devices very recently with Apple Silicon. The iPhone 15 Pro apparently doesn't seem to dim the screen even when playing very demanding games, which certainly isn't something you could say for previous iPhones. If the M3 powered iPads of the future (or even A17 Pro iPads) are able to do this as well, I'd say that's a remarkable achievement, given Apple previously had to utilise screen dimming to kind of bridge the gap. Of course, the iPhone 16 Pro and iPad Pro M3 could go right back to the way things used to be before so this is just speculation.
But if this is the new floor going forward, I think it's a significant landmark. And one that conveniently comes just as Apple is actively pushing AAA gaming on iOS and iPadOS.
One question I have is that since laptops and desktops are not fully interchangeable with desktops trading portability for power, why do people think iPads and MacBooks should be 100% identical? Unless you're Marques Brownlee lugging an iMac Pro around an airport, most people don't bring their desktops when they travel. People are always trading off portability for power. It's ok for desktops and laptops to be segmented computers with people often owning both, yet Apple is bad (maybe not to you, but to people like Luke Miani or Tailosive Tech who are both openly hostile to iPads) because it's not ok for laptops and iPads to be different devices with different capabilities. They must be 100% alike or else the iPad sucks. Some things will always be easier on one device than others whether it's due to form factor or user interface or app availability. You'll never get 100% overlap.
With desktops and laptops, particularly with Apple silicon, I think we've hit the point where you can say for the vast, vast majority of people they aren't that different. I'm pretty sure not even MKBHD takes a desktop with him anymore. There is still some difference in power technically, but after the last few years, not one that you could use to make an analogy between iPads and laptops.
Thank you for being one of the very few people online who is willing to delve into these discussions without falling into dogmatic tribal arguments. Something I noticed with you a year or so back in a contentious thread that was talking about the A12Z dev kit in which you came in and added a bunch of useful info.