There is a chance we won't get definitive edition. Act 3 barely works on PC, so in few days we'll see how poorly it looks on Macs. How do you expect more things to be added? Now add the new voicelines for Karlach from patch 2 and you see that it's very not likely
BG3 currently holds Steam's #7 spot for highest peak players (beating Cyberpunk 2077), and only recently fell from #2 to #3 for highest concurrent players, beaten only by Dota 2 and Counterstrike. And it's an indie CRPG.
It beat Divinity 2's numbers by nearly 10 times, and this isn't even counting non-PC numbers.
Seriously, the game's success can't be overstated. To think there won't be a definitive edition is kind of nuts, IMO.