Wouldn't it be neat if computers were modular?

You buy a processor today, another tomorrow, then a couple more RAM chips, and keep buying until you have a monster beast!

Maybe an individual could own a supercomputer in his lifetime, then.

Damaged a processor? Replace it for another.

Now, I realize that, from the little I was taught about computer architectures that there are issues with this idea. The bus is one, I believe. So perhaps, it could only be modular to a point, it would still be neat.