The teams who have done the best are those who have built salary-efficient teams that don't need much fiddling with. There is no question that this is the best way to be successful. This is very expensive, though, and the top teams in the IPBL spent upwards of $20 mil on their roster, which has taken several seasons of essentially marking time. However, there are also teams who do well enough to get into the playoffs and try to get over the top with one or two additions at the end. This has not worked out well for anyone in the past. A couple of seasons ago, we had a team that added $200k players in every position two weeks before the end of the season but still lost. It's a question of which you value more - the more successful strategy of taking it easy for a few seasons and then buying a bunch of expensive but low salary players or the, so far, unsuccessful strategy of trying to win every year.
I suspect that this is more of a more with micro-nations because of the limited competition even in the top league. Typically one team will win both cup and regular season and this works out to a big financial edge which keeps the team dominant.