Not surprising though. Lots of people's tastes on here haven't evolved since the 90's gangsta rap/g-funk era. Just pointing it out, not putting those people down, because I love that sound too.
That isn't true either - there has been plenty of recent music I personally have liked. Yes, a good portion of it has been trap and drill music over the last 5 years, but on the surface those have little to do with old school hip-hop.
On the surface.
Once you dig deeper, you can trace an unbroken line of succession from early 90s southern rap, which did not come out of nowhere either to those styles today. And that's very instructive. Southern rap is rooted in a rich a musical tradition and has never really abandoned those roots, and this is why it has had such a strong base for so long and has been able to repeatedly reinvent itself while still keeping that connection.
This is in stark contrast to what we've been hearing from the likes of Kanye West (and now Dre too) for more than a decade, which has basically become hip-hop in name and format only, but is in fact pure pop music.
That's the real problem, not "people's tastes not evolving".
Hip-hop used to present an alternative. Now it has not only stopped being an alternative but in the mainstream it has been taken over by the pop music it used to despise, and that's the pop music of the 2010s, which is actually a very degraded version of the pop music of decades ago.