Fun fact:
F1 goes through regulation changes as fast as sportscar racing does, perhaps even faster.
Group C might’ve died in the 90s but the Le Mans 24 Hour still continued. Prior to that there were many different classes that filled the niche of sports prototype racing. Now we have LMP1 which will last until the rollout of the Hypercar class; LM-H.
The most important thing is the trophy at the end of each season. F1 will continue into infinity as long as it’s the peak series. It doesn’t matter who owns it or what the ruleset is. They could go back to rules limiting it to 4-cylinder open-wheelers built by old British weirdos in their back shed and the sponsors will follow. Like that time F1 was held within F2 rules. Remember that?