Have we reached the era of super-teams?
Can a GM build through the draft and compete for the title?
Or has the competition been raised to a level where you can't win without adding a superstar via trade?
I fear the era of super-teams is just beginning.
I think it's possible to build a team multiple ways; however, what we're seeing in the NPBSL is the same thing we see in the NBA... your team is helped massively by underpaying key roster pieces (usually by way of rookie contracts), then using the cap space rookie contracts save you to go add additional pieces until your cap fills up... then keep those pieces by way of Bird Rights. Timing here is crucial - the Spurs, for example, could not have added Magic Johnson AFTER re-signing Chris Mullin, and couldn't have re-signed Chambers without Bird Rights.
The current draft class is only a single data point, but if it's reflective of larger trends, this should scare teams as if young players now don't reach star status until they're on their second (non-rookie) contract, it makes it much more difficult to get the benefit of having key rotation players be underpaid thanks to rookie deals. This means that teams will have to pick the seasons when they spend hugely to keep key expiring contracts on-board with Bird Rights and incur large tax bills in the process.
The best teams will still be super-teams, because there will always be teams out there trying to tank that are selling off talent to teams looking to accumulate pieces... it's just that super-teams will not be able to survive as long. It's going to take a shift of strategy from the Pokemon-like simply "collect all the best players" because you're not going to be able to afford them forever. You have to save up points to pay the tax, take a 2-3 year window, then sell off your players at below market value to get back under the tax.
Also, at some point, I have to think the year-over-year cap increases will fall below 5% - so far, the league hasn't been hurt by contracts constricting cap space because cap space has risen faster than contract increases... but when it doesn't, teams that have valued financial flexibility will be in a better position to capitalize than teams that have gone all-in to re-sign a (probably super-team) core.
Basically, everyone has a strategy until the facts on the ground change. If players don't come into the league capable of dominating in Year 1 or 2 of their rookie deal, maybe people tank less hard... nah, that's probably never going to happen. To the final question, it's probably still going to be POSSIBLE to build through just the draft, but most teams will mix in a wide variety of options, including draft, trades, and strategic free agency signings (or more likely re-signings).