You can buy one without windows installed, but you'll have to install ubuntu yourself. I reckon it's not worth to pre-install one of the various GNU/Linux distributions since the average users of such a device will do a clean reinstall anyways. At least it's 200 bucks cheaper without windows, so theres that.

There isn’t a large market for that. If you want to sell a repairable laptop to the masses you need the features they desire. Windows is one of those things, unfortunately.