I feel like we're more or less saturated in hardware. Video game consoles peaked with the seventh generation in the number of hardware units sold, hitting over 500 million units. The eighth generation was more like the sixth, getting close but not reaching 300 million units. If you include Switch as eighth generation (and all of its sales), then that would put the eighth generation at over 400 million hardware units sold.
The industry seems to have limitless potential for market share on mobile and PC. Consoles? Not as much.
And yes, diminishing returns on visuals seem to be a thing. Compare PS4 and PS4 Pro performance to a PS5 and it doesn't seem as big of a leap as previous generations. SSD is mostly a gamechanger for load times, but not the graphical fidelity. I suppose I'm cool with that though. I'd rather have games on an SSD with rock solid 60 FPS even if the graphical details and resolution aren't ideal.
Lifetime Sales Predictions
Switch: 161 million (was 73 million, then 96 million, then 113 million, then 125 million, then 144 million, then 151 million, then 156 million)
PS5: 115 million (was 105 million) Xbox Series S/X: 48 million (was 60 million, then 67 million, then 57 million)
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima