If RAM makes use of transistors, then what is the point of using cache memory? Is there a single sort of memory that can be used for everything?

Why do we need cache memory if we already have volatile memory in the form of RAM (Random Access Memory)? Transistors are used in both cache memory and RAM. Is it feasible to use a single kind of computer memory for all purposes?

Why do we need cache memory if both RAM and cache memory are made up of transistors? Can only one type of memory be used for everything?

Since both cache and RAM use transistors as their primary building block, it's natural to question why we need two types of volatile memory. This is due to the fact that both cache memory and random access memory are dependent on transistors. Does the computer need many kinds of memory, or can a single type be utilised for everything?