It depends on your use case and workflow. If you're a gamer running only one application at a time then yes, there's generally little point going beyond four cores.
But not everyone's using their machine for gaming.
If you're a developer or content creator, there are reasons to benefit from increased cores count, partially because the software can benefit from those extra cores, but mostly because your workflow frequently includes performing multiple tasks simultaneously.
As a developer, it's also not at all uncommon to have VMs running, a case where multiple cores comes into its own.
In the past couple of weeks I updated my daily driver desktop from an Ivy Bridge I7 4C/8T to a 6800K after evaluating the 5820K, 6700K and mich more recently the 7700K. While I may yet put the 5820K back in (despite being older it overclocks far better than the 6800K), I found the 6700K/7700K still limited my workflow in the more extreme scenarios, typically when using multiple VMs.
I still would hold fire on Ryzen until it's had time to settle in. For example, it wasn't clear until some weeks after Broadwell-E was released that it was a crap overclocker compared the the previous Haswell-E, and that you're generally better off going for the Haswell-E series if overclcoking is your thing.