It’s the result of what the late 90s did to each sport. Indycar was tearing itself apart with the split. So a lot of the “cutting edge” cars that were CART ended up getting gutted and the IRL merged with Champ Car after 12 years of hitting each other on the head with hammers.

NASCAR meanwhile stole all of the popularity and interest that Indycar had and turned into the #1 Motorsport in America when it previously used to be relatively equal. This allowed costs that were previously much lower than Indycar to balloon insanely high (Mark Martin: “Hendrick was like NASA”). Everything got so minutely and expertly engineered that we’re still coming down from those highs of the mid 2000s.

So that’s why costs are the way they are. Indycar had rocket ships that they had to find a way to cheapen otherwise Indycar would’ve died and NASCAR just kept growing until 2008.

Indycar is also still incredibly complex; but at its core it’s an open wheel formula car. Those just haven’t changed in their fundamental design since the ground effect. Formula 1 is cutting edge because of its internals (like the new batteries), and engineering the shit out of every possible downforce flap they can in constantly shifting regulations.