Does linux support from manufacturer really matter?
Only they can truly answer for themselves, but from a business standpoint, yes. It might. Being able to get support direct from the people who made/sold the laptop, whether it be in the form of a warranty or tech support, could save you from having down time when you need to be working.
Not to be rude, but you might want to take your own advice. I see a lot of hyperbole in your two, frankly, rants. “Greybeards” might have ruined your experience, but most people around here just want to help.