I'm in the same boat. Part of it is the medium has so much choice now, and the other part is that we're adults with both more money and less time to spend on things.

I remember playing a handful of NES games countless times, and being able to beat several of them in a single sitting.

I think some people manage to hold onto that (see speedrunners and/or world-class players of this or that game), but you'd have to be very intentional about it.