How extensive will Flash become?

I see today that Flash is growing quite rapidly (at least from what I’ve seen). Adobe’s site is now predominantly Flash (although in some ways I think they did this to show people how well Flash works).

A lot of the rich web applications by Espn, and other major broadcasters are in Flash. Flash is now basically the world’s standard video format.

My question is: How far will Flash go? How much will Flash replace Php and html? I personally like Flash a lot, but I feel like a lot of times the program forces developers to reinvent the wheel (by adding custom hotkeys and custom back buttons, instead of just working with existing web standards).

Oh yes, and how do I make it so that when the user presses the back button on the browser, data is sent to Flash (instead of having the browser literally go back to the state before the user entered the flash).