That likely won't happen unless the service becomes unprofitable. Which, given the demand for fast internet around the world and the drop in launch prices, can only happen through competition.
This will determine how many customers they need to stay afloat.
The second key question is, are there enough customers that can pay $100 per month for service?
If not, Starlink will crumble.
You have to be fairly affluent to be able to afford $1200 per year for Internet service. If you can afford it, a lot of people would like to sell you terrestrial service for less.
That is what I expect in poorer countries to happen. Starlink may claim that one terminal is meant for one household only, but they will silently tolerate connection sharing as long as it gives them penetration.
And third world metropolises aren't exactly penetrated by optic networks. So the alternative is probably an overloaded 4G network.
This is of course a failure to regulate the telecommunication giants, which get fat and rich in the big cities, but are not good at connecting remote locations (this doesn't earn them money).
On the other side, Starlink was very helpful in setting up emergency WLAN hotspots in the disaster area of the recent floodings.
I really liked that, it was a good illustration of how global orbital coverage can improve lives even in rich countries.
If there is some real movement of people in office jobs now working 100% remotely moving to the countryside I can see how Starlink would be a good proposal. It's a small increase in internet costs with a much lower cost of living than in a city.
Elon Musk recently said SpaceX needs $30 billion for Starlink to survive[1] (meaning it isn't profitable now).
He also said that they are aiming for 42000 satellites.
And he said, that they are losing money on the Starlink terminals ($500 / unit).
Starlink is $99/month. If a Falcon 9 carries about 60 SL satellites, and they are aiming for 40000 satellites in orbit, that means they need to do 666 Falcon 9 launches every 5 years. That's 11/month, btw.
Even, if reused Falcon 9 launches are as cheap $10 million/launch (I don't think anyone outside SpaceX knows the actual price). That's $6.7 billion in launch costs alone every 5 years.
$6.7B/(60 months * $99/(month*customer)) = 1,127,947 customers
So they need at least 1,127,947 paying customers to cover launch costs alone just to renew the sky-side of the network. That doesn't include the cost of producing the satellites, ground infrastructure (including terminals), bandwidth cost when connecting to the rest of the internet, staff, marketing, etc.
Now, of course, Starship may make the launches cheaper, and 1.1 million customers is not completely unlikely. However, if he already foresee the need of $30 billion now, their costs are probably significantly higher than my estimated launch costs above.
So let's hope we will not be left with an abandoned constellation of satellites that ends up causing the Kessler Syndrome, because SpaceX abandons the endeavour or goes bankrupt 5 years from now.
[1] https://www.businessinsider.com/elon-musk-starlink-spacex-ba...
For future profitability of the scheme, I consider the terminal price to be pretty important. They cannot really afford to lose money on it long term. Fortunately, manufacturability tends to improve over time.