Enough Musk Spam

The number of people willing to put up with the round trip latency to GEO is relatively small. They would only do it if there's no other option. There aren't enough customers to justify the kind of mass deployment Starlink needs to be profitable.

You can put lots of sats in a low orbit and get low latency, but then they either need to be replaced every few years (the kind of capital expenditure that companies are allergic to in the long run) or self-boosting (expensive, and still eventually need to be replaced). You can put them in a higher orbit, but latency goes up noticeably, you need even more sats for coverage, and it's more expensive to put them there. You can put them in GEO and use fewer sats, but latency goes through the roof. These are the options orbital mechanics and current technology allows.

If we had a space elevator or similarly cheap way to access space, then it becomes more viable. Note that while Falcon 9 and Starship potentially make it viable to build one of the space megastructure ideas that have been floating around for decades, it would also crater SpaceX's business model. Chemical rockets would build their own demise (at least for launching from Earth, and there are probably better technologies for scooting around the solar system once you're up there). Musk likely knows that and would fight it.

Or you can build fiber to peoples homes and leave satellites for Antarctica or the Himalayas or such. That works, too.