The star link network is actually remarkably cost effective in getting internet access to rural areas. There's a reason that these areas still have poor connectivity: it's just not cost effective for anyone to build land based infrastructure there.
SpaceX spend a few billions on StarLink. But if you look at how much network operators have spent over the years on cables, base stations, etc. it's not all that much for a network that offers high bandwidth access all over the planet.
Adding 100K more satellites is going to make Star Link a direct competitor to many of these operators.
It occurred to me after reading the original story that if space based internet gets fast enough, we'll stop using any other kind for most purposes. That means, as a platform, SpaceX could carry a significant amount of the entire world's internet traffic. No wonder Elon is interested.