Lots of games that are fine on Intel Integrated graphics out there.
I'm not buying GPUs that expensive nor energy consuming, no chance.
In any case I think Maxwell/Pascal efficiency won't be seen anymore, with those RT cores you get more energy draw, can't get around that.
I've wanted to upgrade but overall I'm more concerned about power consumption than raw total performance and each successive generation of GPUs from nVidia seems to be going the wrong direction.
That's not the end of the world for me if I move to a 5070 ti and you are quite correct that I can downclock/undervolt to keep a handle on power consumption. The price makes it a bit of a hard pill to swallow though.
I upgrade GPUs then keep launching League of Legends and other games that really don't need much power :)
I built a gaming PC aiming to last 8-10 years. I spent $$$ on MO-RA3 radiator for water cooling loop.
My view:
1. a gaming PC is almost always plugged into a wall powerpoint
2. loudest voices in the market always want "MOAR POWA!!!"
1. + 2. = gaming PC will evolve until it takes up the max wattage a powerpoint can deliver.
For the future: "split system aircon" built into your gaming PC.