Latest incarnation of NVENC changes things up a bit but there are still situations where people will want or need to be using software, though if you get really into it you are better off using external capture and a dedicated streaming machine anyhow which changes things up again.
It gets pretty complicated as both single thread, core count, latency and bandwidth have an impact on streaming performance and also an important factor is whether someone is just doing basic streaming or more advanced stuff mixing in multiple sources and/or effects, etc. etc.
The 7950X3D has some disadvantages in that any non-trivial streaming you will have to mess about a bit to make sure it isn't messing up game utilisation of the 3D cache, the 7950X has lower gaming performance vs some of the Intel options, the 7800X3D is a bit lacking on the core count side if doing anything non-trivial streaming wise. The 9000 series so far don't really change that up. Generally the Intel options are just better.