Nothing, and so they do. Dell will sell you an XPS 13 with Ubuntu installed. Lenovo will let you select Ubuntu or fedora in some models. System76 and Tuxedo will sell you a bunch of laptops only with Linux. Starlabs sells Linux laptops. KDE sells a laptop. Purism sells Linux laptops.

Did you just assume no one sells a Linux laptop?

Man will never be free until the last king is strangled with the entrails of the last priest.

• Denis Diderot

Nothing Microsoft ever does should be trusted or relied upon. They are a bad actor who always operates in bad faith and should be treated as such.