That's why it is encouraging to see AMD's R&D expenses go up every quarter. Now that Zen is giving them decent revenue, AMD now has the funds to do things a little better.
Even so, the development timeframe for new silicon is looong. It will take ages before we see the full impact of it all. Next-gen consoles will pump a lot of extra money into AMD's GPU division, especially now that Semi-Custom is now merged with RTG.
TBH, I see AMD having ray tracing in an upcoming architecture, perhaps not lower-end PC Navi but at least in their later Navi or next-gen parts. I don't see MS going so heavy into DXR's development if they didn't have plans to use it in a console or across a wider range of PC hardware.