[chucker]

I think Apple is trying hard not to repeat a Windows 8, which was bad for existing users who felt uncomfortable with the changes, and not better enough compared to the iPad for new users. They toned the radical release down in 8.1, and further in 10.

(Would shipping an iPadOS-like completely separate Windows Tablet 8 have worked for Microsoft? I'm not sure.)

I don't think there's a long-term trajectory where the Mac and the iPad are the same thing. Instead, I think there will be things that remain unique to the Mac, and things unique to the iPad. Which ones? Who's to say. Right now, only the Mac has things like Full Disk Access and dual-boot, and only the iPad has a home screen and touch. Merging those too much runs risk of a jack of all trades, master of none situation.