Hi Sean and thanks for reading and commenting!
There will actually be some new model Intel-powered Macs in the coming months, so I’m afraid your Macbook Air may not be a collector’s piece after all! :-(
Yes, it is almost certain there will be ARM-powered Macs coming out in 2021 — possibly earlier. Yes, I expect they will be lighter, more compact and have improved battery life. I also expect they’ll be better at certain tasks — as Apple will be able to bake specialist features into the silicon. ARM Macs will be able to run many iPhone and iPad apps natively. And I don’t expect the laptops will have a fan, either.
Apple isn’t just doing this to cut costs. It’ll be extremely confident it can make superior Macs, too.
But I expect your Macbook Air will still be good for a few years! :)