You're asserting a lot of things without any specifics to back them up. I've been using Linux-based systems for a long time and the quality of the kernel has never posed any sort of practical issue for me.

If Linus had chosen a small team and taken his time to do anything I'm sure the Linux kernel could have ended up like OpenBSD or similar systems. A very high quality OS that takes its time to do everything to the point where users more interested in a practical OS would have looked elsewhere.