That's only true if you make a point of buying hardware you already know there's linux drivers for. I work with a few headless linux boxes, but not a GUI. Every year or two I try a distribution or two on whatever hardware I have, hit a problem, sigh after reading through numberless blog/SO/reddit posts contradicting each other on what's possible, and abandon the attempt.
I have a 2018 Dell XPS 15. From what I've read, there's only an 'experimental' (ugh) driver for the fingerprint scanner. To switch between integrated/GPU graphics, you have to log in and out (or you don't - depending on who you read). Not sure about the touchscreen, but I can't summon the motivation to find out. So much depends on fiddling, experimenting, and reading. I'd rather go for a run, and put up with Windows (which I loathe, but loathing seems to be a precondition of computer use in 2018).