S&P500 - Mag 7 & Meh 493?

Been hearing about how the S&P is being carried by the mag 7 and without those, its performance would be pretty meh. (this may have lessened this year but more of a conceptual question anyway) Just wondering if there is any causal relationship there, i.e. the rest of the S&P is underperforming not because all the other companies are relatively moribund, but because the mag 7 are taking up all the oxygen from the meh 493, and if the 7 weren't so mag, the 493 would be less meh. I realize reality i