Pretty sure lactose intolerance would have ZERO effect on a blue milk drink success if it actually contained milk. Although it was called blue milk by fans, I don't think it's bee canonically called blue milk. Unless the D23 display counts as cannon.
Many adults are averse to milk for some odd reason, I drink tons of it. My teeth and bones are ultra healthy. No breaks, and no cavity until I was 40.
But regardless, I absolutely want some sort of meal served with "blue milk". It made a reappearance in the new movies, so it is still current.
It's arguably the most famous fictional drink from a movie ever. Not having it would be a MASSIVE fail by Disney. Of course, not having THE Cantina in a Star Wars Land would also be a huge fail....
Although besides Butterbeer, Universal has some fails too. The Flaming Moe is awful, as are many other Potter drinks. Especially the fake sweetener ones.
Add in the plastic cup, with Galaxy's Edge imprinted on it, and my $13, who are we kidding, $20, is ready.