The number of satellites is not relevant. It's a single parameter a large number of them which describe how well the constellation will perform. Please see here for more detail:
The satellites are not the hard part, even though they are extremely hard. The hard part is going to be getting a suitable user antenna for a low enough cost that they will make the money back. So far they have not spoken publicly about their user terminal or cost, other than a couple sound bites musk said years ago about how low he wants the cost.
https://www.google.com/url?sa=t&source=web&rct=j&url=http://...
The satellites are not the hard part, even though they are extremely hard. The hard part is going to be getting a suitable user antenna for a low enough cost that they will make the money back. So far they have not spoken publicly about their user terminal or cost, other than a couple sound bites musk said years ago about how low he wants the cost.