I have to say first, that i love the NXT shows and it's one of the best things, that WWE has going right now.
Let us look at the concept of NXT. It's basically there, to attract wrestling fans who don't usually like the WWE product to the network. The same with the cruiserweight classics. It's basically trying to be the ultimate 'indie' promotion, drawing off all the talent from the actual indie promotions. It's Vince's latest way to dominate wrestling. If the WWE can do indie wrestling, with all the best indie talent, and with their superior production values, how is any other promotion going to rise?
People have to understand the WWE's business model in 2016 is to get anyone with any kind of interest in pro wrestling, WWE or otherwise, to subscribe to the network and pay them 9.99 a month. Raw ratings don't matter, as long as they stay healthy enough to keep the show on the air and draw in a reasonable amount of new consumers. It's basically like a loss leader for the WWE: protecting their prestige and maintaining mainstream presence. But the ratings don't need to be huge. Their profit is in merchandise (hence their obsession with merchandisable catchphrases and visual gimmicks) and the network. Yes, guys like Shinsuke Nakamura and Bobby Roode are huge with a certain portion of the pro wrestling audience so why put them on Raw or Smackdown and give them away for free when they can put them behind a pay wall? Are you a fan of NJPW? Well, guess what, you can't see Nakamura anymore unless you subscribe to the WWE network. Are you a fan of TNA? Guess what? We have Bobby Roode here. It makes total sense when you understand the WWE's business model. Do they 'need' Nakamura and Roode on the 'main roster'? No, they probably won't affect their audience numbers as they won't be well known to casual fans. Do they care if Nakamura's and roode's careers are 'wasted' playing to a small audience? Of course they don't. NXT is not a developmental department, it's a marketing strategy.