The current V6 Turbo engines with advanced Energy Recovery Systems were introduced with two major ideas in mind; 1. It would make Formula 1 engines relevant for road cars. 2. It would attract new manufacturers to the sport.
1. Failed miserably; there is 0 road relevance for F1 engines. 2. Failed miserably; only Honda entered the sport and they are pulling the plug now. Juicy detail; they extended their IndyCar contract and IndyCar is switching to V6 Turbo Hybrid engines in a few years.... So the "carbon free tech" reason they gave to pull out of F1 isn't entirely true.
What F1 should do is one of two things;
1. Find a way to become road relevant again. I'd say the only way to do this is to skip Electric as Formula E is doing this already and go for hydrogen fuel.
2. Screw road relevance, and focus on entertainment. This means abandoning the insanely complex/expensive engines and go for simple, powerful, and most of all cheap engines.