There has been a major turn in the way NXT has been perceived and treated by WWE higher-ups. After getting a two-hour slot on the USA Network in September 2019, a huge push was made to elevate NXT to the "third brand" and remove the "developmental territory tag" it had, though many would argue that it successfully did so a few years ago.
However, the nature of NXT call-ups has been different. With top-tier talent stepping up in the men and women's division, it appears as though there has been an emphasis on having Superstars stay in the brand for longer and grow more.
Gone are the days where Superstars would simply debut after WrestleMania. Bryan Alvarez spoke on WOL(H/T WrestleTalk), revealing that WWE has had a change in approach in how they plan to draft talent from NXT to RAW or SmackDown:
“Back in the day everyone used to get called up after WrestleMania. I think a person or two might get called up after WrestleMania, but now they’re trying a lot harder to only call people up when it’s time to call people up when there’s been plenty of time, storylines have been finished in NXT, people have been written off the show. That’s most likely when it gonna happen.”
This explains why Superstars like Adam Cole have been able to spend close to three years in NXT. Had it been a few years before, he likely would have had a one-year run in NXT and moved to RAW or SmackDown because he was deemed "ready". That isn't the case anymore.
The cream of the crop in NXT are all "ready" for the big stage, but we're glad to see that WWE has learned a better and more efficient way of transitioning talent from NXT to RAW and SmackDown.