That's a ground station, not towers. The "towers" are the satellites. And the number of grounds stations you need doesn't really have much to do with how much bandwidth you use, because they can use directional wireless or laser communications at higher power levels than ordinary devices, so they're not the bottleneck.
The reason to have a large number of ground stations is so that there is one within range no matter where a satellite is. But they have plans to build an inter-satellite mesh that would remove that requirement as well:
https://hackaday.com/2019/05/20/everything-we-know-about-spa...
In principle if they wanted to serve a higher density area they would need more satellites so they could each cover less area, but that's not really its purpose. Dense areas can more than justify a fiber network. What the satellites get you is world-wide coverage from one network, particularly including the places that don't have existing coverage because their density is too low.
And the combination of that doesn't leave much left for cellular to do. You have a very high bandwidth fiber connection at home, at work, backing the wifi in any kind of a hotel or coffee house, and then Starlink for when you're in a rural area or in a car and you want to look at a map but aren't near any of those. What's left for cellular?
you know how big the starlink antennas are? They don't fit in smartphones, not the directional ones.
I suppose if you're out in the middle of nowhere away from both any building with fiber and any vehicle with Starlink then cellular might be useful, both those are also the kind of places without any cell reception.
Starlink, Cellular and ground based internet serve different points on the density /mobility curve.