1660Ti should be good for at the very least 2 years. Depends on how the RayTracing tech goes. If devs start pushing it in all games, requirements may increase faster but the 1660Ti should last 2 - 3 years as psycho says
agree @psychoman but my point was, if it saves development time, they might think it's too costly or time consuming or both, to implement both lighting techniques. I hope current lighting algo's remain too. Sometimes it suits certain scenes better imo.
Well, Ray Tracing is not as easy and as fast as Nvidia makes it out to be. Often times devs will need to manually tune the light source, because you don't always want the source of light to emit it equally as bright light in every direction. Is it faster than artificial lighting? Yeah sure, but it's not a couple day job either like Nvidia would like people to believe.