A better implementation of the budget cap

With the same budget cap for all the teams, it seems like if one team gets their first car right at the start of a regulation overhaul, and some other teams goes in a radically other direction, it is going to be really hard for them to catch up to the teams at the front. Because while other teams focus resources on bettering their relatively words cars, the top teams can instead focus on perfecting their already great car.

I was wondering how an implementation of a sliding scale for the budget cap, just like like wind tunnel time, might lead to closer racing. Perhaps it can't be as drastic as 5% per position as in wind tunnel time, but maybe something along the lines of 2% per position or so.

What do you guys think would be the pros and cons of such an approach?