Linux Kernel Rookit stopped making?

Question

linux

Has Rootkit ring0 been discontinued or are old developments doing their job well? 2 hours of googling in the English segment only led to news about more or less modern user-level rootkits.
News and all sorts of LKM rootkit are dated 2002-2006.
So the question is: Kernel rootkit stopped being written because:

1. Linux has become more advanced since that time, and such rootkits are no longer written.
   
2. Old linux kernel rootkits are still relevant
   
3. Now actual rootkits ring-1/ring3 etc.
   

Thanks in advance.