That's the end goal we are working towards to yes. Dolby has a 4000 nits monitor for mastering and their end goal is 10000 nits. Sure that is not literally bright enough that you need sunglasses but if there is a daytime shot with a bright sun, the sun should be so bright that it should be uncomfortable to directly look at it. You know just like in real life.
Except in real life we avoid looking at the sun. When watching a 2D panel in my home, I don't want to be made to look away from the display. That's is simply taking it too far and I'll have turned HDR off if that's where we wind up. Hopefully more players follow Oppo in including a strip metadata feature while passing Rec. 2020.