MacBook Airs do not use flash, they use SSD like MacBook Pros. iPads use flash. Flash is materially slower than SSD which can cause performance issues on swap and this can result in more power usage and more heat.Sure, but obviously, the iPad Pros can handle the M1-M4. We’ve seen these iPads running games, LumaFusion and the like. These give us an idea what performance is like under heavy load.
Using macOS, the thermal limits of the iPad will remain the same. The iPad will likely just see throttling sooner but I doubt it’s as bad you seem to be expecting. If it were that bad, then performance on demanding iPadOS apps would be worse.
These points are moot for dual boot.
If Apple by some twist of fate allows dual booting, then macOS will be running on bare metal hardware. It won’t be subject to iPadOS memory management. It will be using macOS memory management while booted to macOS. That includes swap behavior.
I also question the veracity of the claim the iPad “SSD” is slower than MacBook “SSD”. The storage controller is just part of the M-series chipset so on the controller level, performance should be the same given the same chipset. I’m betting Apple just orders their NAND flash in bulk from multiple vendors. I doubt they’re specifically putting better NAND flash chips on the MacBook Air than on the iPad Pro.
iPadOS/iOS does lean more towards power savings. However, we’ve already seen how macOS performs on Apple silicon. Perhaps the impact on the 11” Pro (~60% battery capacity of MBA) would be pretty heavy but it shouldn’t be as bad on the 13” Pro (~80% battery capacity of MBA).
Also, there are plenty of folks who use the iPad while docked/plugged in. Concerns about battery life are a non-issue then.
P.S.
I very much prefer to use iPadOS versus macOS on the iPad precisely for the touch-optimized UI/UX and apps. With that said, I can see the value in allowing macOS on the iPad as a second operating system that a user is allowed to install themselves. I certainly don’t want macOS installed by default (either dual boot or virtualized) as it would eat up precious internal storage for many users who won’t use it. Of course, I doubt Apple would do it since that would jeopardize their Services revenue. Heck, if they can get away with it, I’m sure they’d like to implement a closed model similar to iPads on Macs.
Whatever example of an App running on an iPad is largely moot: these are done in a relative vacuum. iPadOS like iOS is fundamentally based on single card views and single task funnels. You can run an App in iPadOS and it runs that, which most of the heavy Apps are scaled down versions of Mac Apps. The iPad won’t have much going on in the background. But in MacOS, you can have lots going on in the background.
macOS, relative to iPadOS, is in many ways limitless in its multi-tasking capability but iPadOS is extremely constrained in that area.
Thermal limits on the iPad are reality. Apple doesn’t put fans in a MacBook Pro because they felt like it. It’s required to get sustained power throughput as is air intakes in a sports car with a high performance engine.
MacBook Airs throttle a lot, even with Apple silicon. Power throughput on some heavier sustained tasks can fall off of a cliff. Not so with the MacBook Pro or Studio as examples.
The iPad cannot handle macOS. What Apple has done with iPadOS is good with making virtual memory more robust allowing things like Stage Manager. But it’s a device designed to be efficient and mobile, and this limits its power and what operating system it can reasonably run.