Is There a Convergence of Data Base Components?

Some in memory data basis store data just in memory, so l there is no access to disk at all. And some in memory data base use disk for some of the things. I assume it's not as easy as some inner face with like write and read, and you just implement them. But ultimately, if you were accessing the disk in the end, i would say that store tension is still something that, well, is below the in memory cashes. So does that mean that there could be some sort of convergence?