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.
So it's up to me now to tell you: If you want to run Linux on Apple hardware, help getting it to work! Otherwise please just use hardware with Linux supported by its vendor instead of complaining here.
One great thing about open source is that everybody can work on what he needs or what he enjoys. So if people enjoy working on flicker free boot, that's great. Other people enjoy reverse engineering Thunderbolt adapters to get them to work with Linux or dig into the depths of the state machine required for touch pads to properly work. In the end we all benefit from such work, as each little piece gets us closer to the completed puzzle where everything works smoothly.
It seems unfair to compare your mac experience on a mac to your GNU Linux experience on a mac.
I don't think it's a big deal at all. Or rather, I think it's important, but it's the last bit of polish that you put on things after the rest of your house is in order. It's a nice-to-have.
Meanwhile, I installed Debian buster on a 2016 MacBook Pro -- a two year old laptop -- and sound and suspend-to-RAM don't work (hell, the keyboard and trackpad didn't even work at all without installing an out-of-tree driver post-OS-install; I had to do the install using a USB keyboard). Yes, I get that this probably isn't super common hardware, and it's also a bit exotic, but... c'mon. I just don't care if my screen jumps between text and graphics mode or changes resolution a couple times before I get to the login screen. It just isn't on my radar at all.
The Xorg touchpad drivers are a mess: libevent is one-size-fits-none, synaptics is buggy and unmaintained, and the fork of mtrack that's still maintained might be able to come close to something decent, but I'm not sure because I've already spent a couple hours tweaking its settings, and I still can't get it to not randomly send scroll and button events while I'm typing.
So no, I don't care at all about something useless like "flicker free boot". I want my laptop to be actually polished in ways that are functional first.
And I get it: it's not up to me to tell people what to work on during their free time. Everyone has their own itch to scratch, and that's a very personal thing. But to then (as you have) arbitrarily decide that visual polish during a functionally-irrelevant period of the machine's operation is more important than day-to-day functional polish while I'm actually interacting with the machine? Nope... not buying it.