The GP is referring to all the other Linux distributions who really give you <y> (or <z> or <Þ>), not to implementing <y> on your own.
There are distributions (e.g. Linux from Scratch) for when the option you want is the NULL option—i.e., doing things yourself. But there are N other managed options, not just one managed option and NULL.
Ah yes, the strawman disto which matches exactly what <user> needs and is the reason <problem> isn't actually an issue since they can just switch to strawman distro!
Unfortunately strawman distro is never real and the problems still exist after congratulating the ability to switch to it.
There are distributions (e.g. Linux from Scratch) for when the option you want is the NULL option—i.e., doing things yourself. But there are N other managed options, not just one managed option and NULL.