I don't think we're very far away, the main difference between the G-League and the NCAA isn't the level of competition (or the pay
), it's the ability to build a personal brand and get known. And even beyond the G-League, there are a number of basketball minor leagues in this country that a lot of people just have no idea about, but are played at a very high level (just not, you know, the absolute physical freaks you see in the NBA or among the candidates to join it). We're already seeing people skip the NCAA in favor of the NBL or New Zealand, and while that's probably more culturally appealing to most US-based NBA prospects than playing in China or Turkey or even Europe, there's just a wealth of options for them to get paid and focus entirely on basketball during that year's wait.
My prediction is that if the trend of top NBA HS prospects going abroad rather than to college continues, the NBA will eliminate one-and-done. They'll prefer that rather than risk more of that talent leaving their system (i.e., to keep the AAAA-level players in the G League, rather than having them playing abroad and just staying there if they can't make an NBA roster).