In some respects, i guess you could look at it as a "lull of talent". But i'd actually kinda look at it as almost the opposite.
We do still have some consistent, perennial "elite" goaltenders at the top. It's just that beyond those small handful of names...the way the game is played today, and the way goaltending has developed, there's a ton of volatility and fluctuation among the rest of the names beyond that. Guys rise and fall year to year, and it's a bit of a rollercoaster for some.
But it's really just a reflection of how many decent goaltenders we have these days. Combined with the realization for teams, that gone are the days of a starter playing 70 games a year. Gone are the days of the "veteran backup" who is better at sitting on the bench holding a clipboard doodling or charting faceoffs, than actually tending net. Teams realize that today...you need two quality goaltenders, the lesser of which can potentially give you at least 30 games if called upon. The "talent gap" between the multitude in the mushy middle has closed, such that being "fresh" and "rested" and "on a hot streak" tends to be a lot more of a differencemaker than any actual difference in skill/talent between all of these guys who are capable enough in the right situation.
It used to be that teams would stash their "young guy" in the minors to get as many games as possible, for as long as possible before making the jump. The idea of "overripening" guys. But the way it is today...that "backup" role is plenty juicy and boasts plenty of potential minutes to justify just moving that young goaltender up as soon as they look ready. If they can contribute...they're going to find themselves on the roster and playing games now. There may be inconsistencies that result from that, but on the whole...it still seems to be the more favourable approach, compared to just riding your "starter" into the dirt and losing a few games with your veteran backup who is basically a sacrificial lamb for back-to-backs, etc.