That is great racing.
But the street platforms of the various current Cup participants vary significantly compared to those cars.
IF that changed, it could happen.
But I don’t see it coming. Nor do I see a spec chassis on the horizon as it is the custom --historically and currently-- across all of stock car racing–to build one’s own chassis.
Either would cut costs, but I believe a serious reduction in horsepower (that is way overkill for the current tire anyway) would cut more.
All that said, NASCAR, er, I mean IMSA, took a perfectly good NASCAR-ish easy to work on “Daytona Prototype” sports car:
https://www.google.com/search?hl=en&biw=1440&bih=789&tbm=isch&sa=1&ei=0jRBXP7IC4385gKBubjYAw&q=imsa+corvette+daytona+prototype&oq=imsa+corvette+daytona+prototype&gs_l=img.3...7827.9671..10682...0.0..0.93.662.9…0…1…gws-wiz-img…0i8i7i30.l5FGB3ZJKWA#imgrc=g0qbjcFG1M0MTM:
And replaced it with a largely European spec class car:
https://www.google.com/search?hl=en&biw=1440&bih=789&tbm=isch&sa=1&ei=KzVBXLOjG4aK5wLDpZyQBA&q=2018+daytona+rolex+race&oq=2018+daytona+rolex+race&gs_l=img.3...2238.4539..5131...0.0..0.109.348.4j1…0…1…gws-wiz-img…0i30j0i8i30.q6hYVaHW5bE#imgrc=uUyqdz8M7ZbAoM:
Some of the absolute fugliest cars of all time, imo.
So, gents, who knows. Anything is possible these days.