I don't think he will, he may try it like he did with the EA but he doesn't know how 5e or the game works and my guess is he'll get bored sooner rather than later and drop it. That being said, he playing the game a couple days is already a huge win in terms of marketing for Larian if it happens.
It's a realistic possibility.
Just like how WoW managed to shit the bed a few years back right before FFXIV Endwalker release, causing many content creators from that game to detour towards FFXIV, the recent Diablo 4 patch has managed to achieve the same effect within that community, and it looks like a big number of them have decided that BG3 is going to be the game that they should pivot to.
That Diablo 4 dev jumping into the conversation about how BG3's existence and dev cycle was an anomaly last week was something that did not escape the attention of the community on that side. So it's not surprising the Diablo community went and made a meme promoting BG3 like this right after those patch notes came out a couple days ago.
https://old.reddit.com/r/diablo4/comments/153aarc/just_tested_out_the_new_sorcerer_unique_its/Moving the release date a month earlier was a genius move, even in ways that the Larian devs couldn't have anticipated.
