OK, I can find common ground here. Consolidation in the publishing space might be an issue. Perhaps countered a bit by more accessible self publishing, and the historical precedent of market vacuums being filled organically. By this I mean, any role Activision may have played in publishing independent games could be picked up by a smaller or an up and comer. Someone like Deep Silver or 505 Games. In fact, with one less large publisher in the market, it creates an opportunity for the smaller to mid sized ones.
At the end of the day, though, I don't think this deal will have a radical impact on independent developers. They will likely have been working with or looking for a publisher anyway. Activision used to publish a fair amount of licensed games. They did some Marvel games, TMNT, Ghostbusters and Walking Dead. Some of those games were developed by studios not owned by Activision. But they haven't done that in years. I think in the last 5 years they maybe published 2 games that weren't from internal studios. Call of Duty Mobile (which is an internal IP) and Sekiro by From Software. So it it isn't like Activision was some publisher that had a big impact on studios that they didn't own. EA, on the other hand, has a whole division for that role. So does 2K, they own Private Division who published The Outer Worlds. Activision left that role in the industry years ago.