It's not as simple as that; RAM impacts a lot more than just textures. In open world games last gen, the limited RAM meant games had to be constantly shunting data in and out of memory. This not only resulted in a lot of pop-in and loading stalls, but also impacted performance because the CPU was bogged down by managing all this data streaming. These factors are a big part of why even top tier productions like Skyrim and GTA 5 could run so poorly.
It was also a big headache for developers; ask pretty much any dev who worked on PS3/360, and apart from the PS3's ridiculous architecture, they'll likely tell you that the hardest part was working with such extreme memory constraints.
I hear ya, but we have console with like 10x the memory to work with and generally its not producing a world of difference in game design. Even modern open world games suffer from the same issues of clearing out data after a certain distance, pop in, loading stalls, etc. If you play modern PC games you would also see a big RAM hog (VRAM) is textures. I feel there is also just less efficient use of RAM given there is less limitations to work with. Many of the performance issues on 7th gen were likely due to GPU bottleneck.
Just an example, Gears of War Ultimate is really just the original game with improved graphics. But its somehow a massively more resource intensive than the original game in every way. I mean its still a linear shooter, its essentially using the same code, yet much more demanding. I see that as an example of less efficient use of resources.
In spite of the memory constraints, they did amazing things on 7th gen specs. I also feel the average game would have benefitted with GPU power over RAM.
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