This is just a matter of target audience. I think if you want ordinary people to use your OS a flickering boot will get noticed and not make a great first impression. The users who don't care at all about it are probably already using Linux.

And I agree with you that the basics need to run well first, but in my experience many common distros got that covered. Debian is one of the exceptions, it's pretty much the only Linux distro where not everything runs fine out of the box on my laptop.