That one thing with Linux that is bothering me...

Why are all people creating the same thing but slightly different?

It's great and annoying at the same time, "I don't like snapd", let's create something new.

I have an example where making something slightly different makes much sense... like NodeJS vs Deno, Deno is like Node but well thought, or npm vs yarn...

I'm pretty new to Linux and not a veteran at all, if someone could explain me the difference between Snapd, Yaourt, Zypper, etc, would be amazing and I really like to learn. But I seriously don't understand why people don't use one thing and just improve the crap out of it like with linux. Is Linux a specification or a kernel? If it's a kernel and all distros use it, why can't we use Ubuntu packages on Arch for example or vice versa?

I'm NOT saying that Linux is crap it's fookin badass. But I'm just trying to understand and I know I get slapped because of this post, but I rather ask a question then not ask at all. Links are also welcome.