In terms of the viability of RT on next generation consoles, the hardware doesn't have to be specifically RTX cores. Those cores aren't the only thing that matters when it comes to ray tracing. They are fixed function hardware that speed up the calculations specifically relating to the BVH intersection tests. Those calculations can be done in standard compute if the computer cores are numerous and fast enough (which we believe they will be on the next gen consoles). In fact, any GPU that is running DX12 will be able to "run" DXR since DXR is just an extension of DX12.
Hmm, some hope for RT sooner than 2025 then? In terms of wider adoption.
https://www.eurogamer.net/articles/digitalfoundry-2019-metro-exodus-tech-interview