Are cap-weighted small and mid cap ETFs de facto self-limiting on growth long term?

For example, if a company is in the S&P400 midcap etf, explodes and ends up"graduating" from the S&P400MC index , wouldn't that have a significant limiting effect on the longterm upside compared with cap-weighted etfs that only track the top end of a given market(SP500/NASDAQ100)? In that situation, the largest cap company(and arguably most successful w/in the index) in the index gets removed and the n-1 of qualifying companies smaller than the smallest company in the index gets added to the ind