I think the problem is that by the time GTA 6 releases, PS5 will already be close to 100 million sales. That means that it would already have sold the clear majority of its lifetime sales at that point, unless you expect PS5 to top 150-160 million sold units eventually.
I think the only major thing GTA 6 could do is to make PS5 sell more than PS4 in lifetime sales, but i don't think it can't boost it much higher than that.







