It’ll take longer for two reasons.

One is that it’s a more complicated part with tougher fab requirements.

Two is that it’s not a commodity. AMD can’t make nVidia GPUs. They have to design their own. Everyone has patents and trade secrets and copyrights. Patents expire and knowledge diffuses but that adds another time lag.

AMD and Intel are fully aware of the demand and are working on it.

RAM is a commodity. Totally interchangeable standard part. Also simpler to fab, thus quicker and easier to scale up.

Oh, and I’d like to add: everyone is afraid it’s a bubble that will pop. Nobody wants a bunch of stranded capex. That has also happened before many times. So that puts brakes on it too.