It's not really a matter of horsepower that ever allowed Portal to exist though. (
Mind-blowing gameplay possibilities mostly come from mind-blowing game designers making stuff they envision before it's ever put into a computer, high-powered or otherwise.
(It does however take some complicated camera and perspective techniques which benefits from having powerful computers and fast data to help realize it and work with it to make a fun game of the tech; I'm not sure how the planned Zelda would have worked completely or what limitations it would have dealt with even though
they did get it prototyped, but I could see it being a lot harder to work with even after they got the base two-levels-connected-by-portal concept prototyped. This Portal demake benefits a lot from the tech being worked out already on other machines, allowing the designer to understand the technique and reconceive it on the lesser hardware.)
Even if a game used exponentially more powerful hardware for mind-blowing gameplay possibilities, would people notice? Gamers are mostly hung up in AAA production values (where the exponentially more powerful hardware gets used, on mind-blowing gameplay or otherwise,) there's indie and off-beat stuff out there which has really cool experimentations with tech yet it goes unnoticed often if there's not stars or brands or a big marketing push. LEGO Builder's Journey has some very advanced lighting systems, but it looks like a phone game. Teardown has some phenomenal simulation systems, but it looks like Minecraft. Superliminal is a fascinating combo of physics and angle manipulation to build mind-bending puzzles, but it can port down to Switch. Dreams and Crayta and Fortnite Create and other game-makers and phenomenally flexible realtime game making apps, but most of the games made using any of those apps tend to end up resembling bad copies of other games we're familiar with.