The budget for marketing has doubled the cost of the entire previous game. Does anyone need ads for GTA6? Wouldn’t just having the devs do livestreams of them playing the game and discussing the tech involved with making GTA6 not create enough hype? Does there even need to be additional hype created?

There is a bit of an "arms race," where other games/entertainment could steal GTA's engagement. Eyeball time is finite, and to quote a paper, "attention is all you need."

You aren't wrong though. Spending so much seems insane when "guerrilla marketing" for such a famous IP would go a long way. I guess part of it is "the line must go up" mentality, where sales must increase dramatically next quarter even if that costs a boatload of marketing to achieve.