My brother asked me why all facebook games are laggy, why don't the developers think of a way to improve it?

Yeah man.
Adobe Flash sucks, I know it the first day I touch it.

I wonder it's the architecture itself that makes it so difficult to be improved, or the developers simply don't have the thought of making a better platform.

I don't see a future of Adobe Flash.
How do you make everything cloud-based using a super laggy platform?

That's why I'm with HTML5.
At least it's backed by Apple, Google and Microsoft.
They will do something about its performance.