Question: What was the earliest time Bitcoin could have been made? What tech was necessary?

I was reading through the Bitcoin whitepaper and I was struck by how simple it all is. It's simplicity is beautiful.

But then it got me wondering: what took so long? Was it literally just coming up with the idea? Would Bitcoin have been possible in, say, the early 2000s? Or even before that?

All you really need is an internet connection, a CPU and a small (at least by today's standards) amount of storage.