Could the current computing power we have, be obtained by enough Commodore 64 machines?

Maybe, but we would have to have many orders of magnitude bigger power supply for that. And this is just the beginning. The cell phone based on those processors could weight a ton each.

In other words, an impossibility from a whole bunch of reasons.

We already had a foom stretched over the last 30 years. Not the first and not the last one, if we are going to proceed as planed.