AST has one very large satellite, so it supports higher bandwidth for each device, giving them 18Mbps speed. Starlink satellites, even with gen 2, are smaller but more numerous. So while AST may support 40 simultanuous callers and sell the service to 40000 customers, starlink direct to cell gives you lower bandwidth but can support 40000 simulatnuous callers and sell to 4M people. (numbers are my best guesses)