I think we'll get there with less than a 1000x increase in raw compute due to a combination of factors.
For one, ray tracing in hardware is new. We've had many years of clever techniques to improve efficiency of rasterization in hardware so overall performance has improved faster than raw compute. I think we can expect similar improvements for ray tracing.
We're also likely to see new algorithmic advances that let us get better results with fewer rays. There was a whole course at SIGGRAPH on applying machine learning to light transport problems, things like learning probability distributions for irradiance to do more effective importance sampling with promising results. Combined with the advances in denoising there's a lot of potential for improved results without more rays there. Lots of scope to take more advantage of temporal coherence I think too.
On the hardware side there is still room to scale wider for ray tracing. It's getting hard to make transistors smaller or faster bit there's still some room for putting more of them on a chip it seems.
Combine all these and I think we're a lot closer than a 1000x increase in raw compute to real time path traced games. Primary rays might still be rasterized though, it still has coherence advantages.