Reverse it? Personally, I don’t feel that’s possible. Probably the main reason is that the number of years that the majority of racers have been in the sport has declined by a significant amount. When we got into the sport, it “seemed” like the vast majority of people had already been racing for many years — I’d have to guess something around 5-10 years in the sport was typical.
I believe that number has declined significantly (for the “majority” of racers). That makes “selling” the idea of taking the sport back to simpler and less-expensive times a difficult sell. People jump in and out much quicker these days (and have for the past 15 years or so). They get enthused about the image, the speed, the cutting edge “stuff”, and by the time it hits home that this is really expensive and complicated, they are probably on their way out of the sport.
Vintage racing has some great attributes, but I see it as more of a “show” and “demonstration event” in some ways (though there are admittedly some people that take it pretty seriously).
I have some ideas on the direction I would take it “technically”, but once again, this is a tough sell. I’m not optimistic.
I will say one thing — I had direct-drive Yamaha kart for a number of years: hardest Bridgestone tires available, no bodywork (nerf bars and front bumper only), very very simple. It would lap a typical 45 second sprint track maybe 1 or 2 seconds slower than a fully modern setup on sticky tires with bodywork and clutch. Without exception, everyone that ever drove it came back with a huge grin and said: “this is what karting should be” (especially after I told them that my total cost to play with it for about 20 days at the track was a fraction of what they spent on one race weekend).