I don’t see it as being forced, when we have so many places where one can go mining these days.
The belts are then often empty. When you then look at ice belts, where many miner come together even today (it was a lot more cheerful in the past by the way) then I don’t see a problem when planetary belts get combined. If it then also has more and/or larger rocks in them then it will make them only more attractive.
When I go ice mining then I often ask if anyone wants mining boosts. Before you know it do 2-3 miners say “Here” and you’re mining in a happy gang of strangers (I know it sounds a bit like offering candy from a van). This sort of thing cannot develop when players are too spread out and alone in a belt.