Question about kernel updates

[Jaap A. Haitsma]

I saw this changelog in the rawhide build file of today.

> 
> kernel-2.4.22-1.2096.nptl
> -------------------------
> * Tue Oct 14 2003 Dave Jones <davej at redhat.com>
> 
> - More merges from 2.4.23pre
> 

Maybe a stupid question, but I'm just curious: why does RedHat (and also 
other distro providers) do this? Why don't they just ship the official 
2.4.22 kernel and just wait until the 2.4.23 kernel gets released?
It's probably due to the fact that the RedHat Linux kernel is a modified 
version (a fork) of the official kernel. But is this forking/merging 
worth the effort? It takes quite some time to do all this and also there 
is a possibility to introduce extra bugs.

Wouldn't it be better for RedHat if  RedHat just sends the patches to 
Linus and company, and just accept the fact that they maybe don't accepted?

Thanks

Jaap