Verizon competes with T-Mobile and AT&T. Comcast competes with a different arm of AT&T, Google Fiber, various older satellite internet services and now Starlink.

Outside the US, broadband providers are still huge but differences in regulation mean there are five or six of them in most markets.

Overall, I think my point still stands: claiming that you can't build a giant company without Silicon Valley's growth formula is ridiculously narrow. The vast majority of big companies are built by other methods.