(a) there's not much in the way of new iPad-specific app development anyway
I don’t know if that’s true, but if it is, then I think it’s all the more important that iPad app development should not be demotivated. If the iPad ecosystem is stagnant, then I don’t see how putting macOS on it as an “out” could do anything but make that situation worse. And if the attitude is “so be it” then I think that’s short-sighted because how long would Apple support a platform that isn’t going anywhere?
(b) the example of Windows on Mac did not kill Mac Apps, which seems in pretty good health.
To Apple, Bootcamp was a temporary necessary evil because the Mac market was too small and needed the crutch until it had a healthy enough market share and app ecosystem of its own. Having it didn’t kill Mac apps, only because it helped keep the Mac itself relevant while the Mac’s marketshare grew therefore allowing its ecosystem to grow. But had the Mac been able to somehow increase marketshare fast enough on its own without Windows, then Bootcamp would have only served to slow down Mac app growth.
The iPad market is already big, so dual boot wouldn’t be a temporary crutch for the platform, it would just be an ever present ball and chain to the growth of the platform.
Hopefully (c) would be that MacOS on iPad grows the market so that iPad apps are more worthwhile.
The iPad market is already pretty big so I don’t see macOS on iPad growing it drastically. But even if it did, I don’t know how drastic it would have to be in order to make developers want to develop and maintain two versions of the same app on one device. I think the real primary problem is probably not many users are willing to pay for two versions of the same app on one device.
More generally I think all platforms are struggling for developer attention, since if an app can be web-based then that will probably be the focus. That's true for Windows and MacOS, but I think iPad is probably the most vulnerable since it's a smaller market (many iPads sold, but also many users that I suspect spend very little outside gacha games).
Again, isn’t that all the more reason that iPad app development should be encouraged and not discouraged? Or are you saying there isn’t room in the market for iPad apps, and that developers should focus on desktop OSes and web apps?
But all this said, honestly I don’t think slowing down iPad app development is the main reason why Apple doesn’t put macOS on iPad. I think the two main reasons are 1) Apple probably sees the iPad as already basically successful at what it sets out to do, and it sells well and has a high satisfaction rate, so there’s just no compelling reason. And 2) I think Apple sees dual OS as generally a bad UX. If even Windows’ hybrid OS was so unpopular that they had to backtrack on it, then switching between two completely different OSes probably won’t be received any better.
I know some believe it’s the destiny of the iPad Pro to become a complete across-the-board replacement of/alternative to the Mac. But even before talking about what that software would be like, if we want thin and light iPad Pro hardware, then I don’t know if a complete replacement is ever going to be in the cards (or any time soon) at base level due to physics and current tech. I’d venture to guess the 13” MacBook Air is Apple’s baseline standard for macOS performance and battery life, otherwise they probably would have made it thinner and lighter. To have the same thermals and battery size, the 13” iPad would need to be thicker and heavier, making it a worse tablet. The 11” iPad being smaller would need to be even thicker. Until technology gets so good that these thermals and battery sizes don’t make any significant difference (long time to go there), I think MacBooks/macOS will always prioritize performance/productivity and iPads/iPadOS will always prioritize portability/simplicity.
Of course it’s easy enough to just say Apple should make a new device—some say a beefier Mac tablet, some say a Mac keyboard base that you attach your iPad to. But as with any product change, the real questions are realistically what would those UXes be like, and would they really have mass market appeal (or are they just a techie’s niche wish)?
