[antb123]

cloud computing was invented by shared mainframes in the 70s and 80s and charges per MIPS.

Amazon applied open source software to the hosting and specifically the network stack and security stack. The model was already there.

[oblio]

The model wasn't already there. Everyone means the public cloud. Mainframes were at best, private clouds.

[xxpor]

The key was VT-x/AMD-v becoming available.