Those who have anticipated significant change in the engine regulations for the 2021 Formula 1 season will have been left somewhat disappointed. While the aero rules have been granted a complete overhaul, the powertrain will remain largely untouched.
Furthermore, anyone hoping for fundamental change and the return of naturally-aspirated engines will also be left disappointed. Hybrid power units are in F1 to stay, and any deviation from them given their efficiency and the amount of resource put into them would be more damaging in the long run. After all, when faced with a choice between building a sustainable championship and pleasing a few people whose spectacle lenses are rose-tinted, the decision's not hard to make.
Apart from the addition of a few banned materials to control costs and the impending freeze of various components, the 2021 power units will be very, very similar to what we have now, and will be so until the end of 2025.