We know they do paid out of warranty repair for a lot of problems, since people have posted about that experience. The forum search is a good resource. Most cases of broken glass seem to be new machines damaged in shipping. But at least one case of an accidentally broken lid was deemed “not repairable” (Glowforge Not Repairable?).
My guess is that they’ve learned from getting machines back like that that a lid repair isn’t economically viable. It does feel like there’s more to the story than meets the eye.