They do this on Steam all the time, its called…,.
“Early Access”.
Imagine if Blizzard put out two dates of sale: Early access (with caveats) and “final release: date yet to be determined”
Everyone buying the "early access wouldn’t be nearly as vocal.
The whole “Early Access” thing is pretty ingenious (if not sinister! 
)
Last Epoch initially charged $35 for Early Access, with plans on lowering the price on release. Their reasons? “You’re paying for the opportunity to shape the games creation”.
They’ve since changed that and now the release is going to be the same price as Early Access.