Until you can run x86_64 at native speeds, replacing it will take a long time.

I wouldn't even bother mentioning X86(64) in the context of RISC-V. When RISC-V becomes financially viable for manufacturers they'll switch. Cost alone is enough to justify the change. Most of the innovation happening these days is in the mobile sector with mobile devices replacing more and more of the average consumer's computing needs. This alone has made for some pretty nimble software already. Every device sold with one of those ARM-based processors has an Arm holding "tax." ALL vendors are happy to not pay that tax and will be even happier to have nothing to do with ARM Holdings at all (I've heard they're shit to work with). Arm and RISC-V are both RISC architecture; not hard for software to switch. What happens in the mobile sector will trickle down to the rest of the tech industry. Microsoft has even embraced RISC with Windows on snapdragon devices. I doubt the consumer will even notice a difference.

Doesn't have to be native, only fast enough to power gaming, office and extensive image collections. Only one of those requires lots of computing horse and that mainly on the GPU (though there are some offenders like PUBG or Minecraft, the later also slurping up a significant chunk of memory bandwidth)

I already knew RISC-V was/is faster in benchmarks. But does that translate to transparently emulating x86_64 for the majority of use cases?