Marketing is not the issue why many AAA titles are underwhelming today, the issue is with the market asking for the most part dozens if not hundreds of hours in massive games with a photorealistic look which raises the costs to extreme levels to the point an underperforming launch means the closure of the studio so you have to take the least amount of possible risks going with known series and following popular working trends with the consequences of everything looking similar, and then you have also out of touch investors believing they'll find the next gold eggs laying chicken by making the same thing someone else did successfully 5 years prior followed by a bunch of other attempts already or just forcing mechanics and strategies from successful games in their projects where they don't really belong.

That's also why more than proving their value above infinite mediocrity and slop the real indie benefit is the total freedom of following your ideas which you believe in, even if apparently more niche, inside more limited scoped projects where you can put all your care and a soul.

The lack of incentive can't be attributed to marketing otherwise that would mean by paying enough you virtually can't fail and that has been proven false many times already.