I saw an interesting stat the other day:
According to this "built with" site, use of SWFObject (which is pretty much what 99% of flash devs use to detect + embed their swfs) is starting to decline among the "top sites":
http://trends.builtwith.com/javascript/SWFObject
I'm the original creator of SWFObject, so I've looked at that chart a bit, and I've never seen the usage go down in the few years since that site's been tracking js usage.