According to senior reporter Shams Charania, the NBA and NBPA are in talks to lower the draft eligibility age from 19 to 18. This would allow players to make enter the big leagues straight from high school much like LeBron James, Kobe Bryant, Kevin Garnett and others did before the rule was changed back in 2005.
While it isn't confirmed, it's likely that the drastic shifts in grassroots basketball could have had a heavy influence on this decision. There have been players in this era of basketball like LaMelo Ball who hooped professionally overseas before declaring the draft as well as Zion Williamson who likely would've been the number one overall pick if the "one and done" college basketball rule wasn't in place.