You know you are wrong.
If PS4 and X1 weren't a limit to game design then there would be no point in PS5 and XB4 plus any other system that comes after. The fact that you don't see a limitation or how they could increase scope or make a game impossible before doesn't mean it is reality.
Many games this gen didnt really need the power of 8th gen consoles per se. Most of the power just goes into better graphics. However, the biggest limiting factor in large scale games was probably RAM. During the 7th RAM requirements in PC games grew significantly. Muliples times the RAM found in 7th gen consoles.
In the 8th gen however, RAM requirements kinda stayed the same. 8GB was fairly common when the 8th gen started and 8GB is still plenty for most games. VRAM has become important primarily for textures.
Look at Switch, in practice much of its content looks like 7th gen games. Yet its doing fine running Witcher 3 and I credit that to Switch having plenty of RAM compared to 7th gen consoles. I get the impression bringing Witcher 3 to Switch was easier than Witcher 2 to 360. The advent of dynamic resolution also helps Im sure for performance.
Increased specs can certainly allow for games of greater scope or whatever. Im arguing much of that power simply goes to presentation in many cases. I've looked at many games this gen and thought, "did we really need new consoles for this?"
I believe we feel that to a greater extent in the 9th gen. Its gonna be like the 8th gen but even prettier. Dont expect the scope of games to change too much. Also, it takes a lot of power just to achieve 60 fps with 4K.
Crackdown 3 for X1S/X1X (4/5) - Infinity Blade III - for iPad 4 (3/5) - Infinity Blade II - for iPad 4 (4/5) - Infinity Blade - for iPad 4 (4/5) - Wolfenstein: The Old Blood for X1 (3/5) - Assassin's Creed: Origins for X1 (3/5) - Uncharted: Lost Legacy for PS4 (4/5) - EA UFC 3 for X1 (4/5) - Doom for X1 (4/5) - Titanfall 2 for X1 (4/5) - Super Mario 3D World for Wii U (4/5) - South Park: The Stick of Truth for X1 BC (4/5) - Call of Duty: WWII for X1 (4/5) -Wolfenstein II for X1 - (4/5) - Dead or Alive: Dimensions for 3DS (4/5) - Marvel vs Capcom: Infinite for X1 (3/5) - Halo Wars 2 for X1/PC (4/5) - Halo Wars: DE for X1 (4/5) - Tekken 7 for X1 (4/5) - Injustice 2 for X1 (4/5) - Yakuza 5 for PS3 (3/5) - Battlefield 1 (Campaign) for X1 (3/5) - Assassin's Creed: Syndicate for X1 (4/5) - Call of Duty: Infinite Warfare for X1 (4/5) - Call of Duty: MW Remastered for X1 (4/5) - Donkey Kong Country Returns for 3DS (4/5) - Forza Horizon 3 for X1 (5/5)