Separate constructors from teams - I’d love to see the whole field in near-identical cars only differentiated by setup and driver. Alternatively balance of power rules like Imsa could make racing a lot more competitive while keeping constructors around.
I mean, many folks would say that’s what leclerc did successfully in 2021. That’s a bit of a conspiracy, and doesn’t make a ton of sense (gearbox penalty etc.) but it’s not impossible.