The main point of the OP is flawed. We have the NBA season because basketball is fun to watch. The finals are just 7 games out of 82 x 15 + 3 rounds of playoffs. Every season at least 20 teams have no chance of a championship. Why do they bother playing? Last year we had no shot from day 1. Should we have not played our games?
Also, the cap isn't the problem at all. If you want to stop top players from clustering, you have to remove max contracts. If you remove max contracts, Someone signs Durant for over 40m. GS would not commit to Durant because Curry could end up costing 50m. Even Cleveland would have issues with their roster because Lebron could easily get 50m this year.
If there was no cap, we get would more deals like KG's deal in Minny that eat up a team's cap. 10m a year would help keep the top players spread throughout the league.
On the other hand, there are many Celtics fans who indirectly romanticize what GS is doing when they talk like things were great when the Celts were full of top players compared to the rest of the league.