I may be mistaken, but I believe Adobe had to ship an Actionscript 2 runtime forever because they completely replaced it when they introduced AS3. They needed t

I may be mistaken, but I believe Adobe had to ship an Actionscript 2 runtime forever because they completely replaced it when they introduced AS3. They needed to keep the flash player backwards compatible, so the player had to have both runtimes. While it worked, it was a kludge.