It is because Adobe drops support of flash player for all mobile OSes.. Adobe made dumb decision by dropping flash player support of smartphones.. means wp8 onwards, ios7 onward, bb10 onward, android jb onward n all other mobile OSs doesn't support adobe flash player.
Adobe now only making flash player for desktops os...
for mobile OSs their is HTML5 which is still not mature as adobe flash... you can play flash related videos on web but flash ads n other flashing content like online flash games are still not supported by HTML5...
but developers trying to improve html capabilities.
No mobile devices have flash installed. Adobe took out flash embedded software. I don't think any smartphone has flash on their OS! That why you can use it only on computers - notebooks and desktops.
There are apps that have flash built-in like ABC,CBS, NBC, FOX, etc... so you can view their programming. But it in the app not in the OS or web browser!