There are tons and tons of swf's running in AVM1 (AS2) and adobe would be in huge trouble if they discontinued support. There's lots of life.
That said, there's virtually nothing in AS2 that AS3 doesn't improve on. That's not always obvious to people coming from AS2 and it's common to point out the apparent idiocy in making a simple click so hard. Once you've covered the learning curve you will wonder how you ever got it done before. The magic really comes out once you've adopted an OOP regiment and it's worth starting to do small projects in AS3 until you get more comfortable. In time, as2 will seem silly.