Why so few leaders at US companies went to top MBA programs

Outside consulting, Wall Street banks and big tech.. even mid size tech or so many Fortune 500 companies have no leaders went to top MBA progarms.. in Europe or Asia , people are so impressed with my top M7 MBA, but here no one cares?

example: Cisco- no one in the entire top management on the home page went to a top 100 MBA

same with Mid size tech companies , Delta Airlines and so many well known firms

Ive been interviewing with many large companies, and most leaders have not gone to top 50 MBA programs..

Interviewed with someone running M&A with a music degree and no MBA