Why is Flash so hard on the CPU?

Question

Recently I hear Steve Jobs citing this as a main reason to not have Flash on IPADS

Answer 1

The main reason is that a fundamental requirement of the Flash product was for it to work on as many PCs as possible. The approach taken by the development team was therefore to design a product that would work on the lowest-common-denominator of PC hardware. For the most part, this meant PCs that did not have advanced video cards.

Given this approach, and the lack of serious competition, there was not much incentive for Adobe to change their strategy. What finally happened to change this in the new version 10 was new competition from Silverlight and HTML and the desire to add 3d capabilities.

Of course Steve Jobs' objection to Flash has nothing to do with any of this and really boils down to his desire to control (and charge for) video distribution to his devices.