If you buy an M1 MacBook Air, you spend $1000 and you get pretty much an amazing laptop that does everything except flip over and let you draw on the screen.
If you buy an iPad Pro - the new one with the M1 chip - then you have to spend $1100 to get the 13" model, which has less storage than the MacBook. And that's just the tablet - you now have to spend $350 on a keyboard case to actually use it like a laptop. You can also use a pen input with the iPad, which you can't with the MacBook, but that's another $130 please. So you can really jack up the price of the iPad with accessories intended to give you laptop-like capabilities.
So I don't buy the idea that either device is held back so you have to buy both. The device they're clearly positioning as a do-everything machine is the most expensive one in their lineup.