Flash is proprietary.. originally owned by Macromedia, now owned by Adobe.
It is not open source, beyond a few recently published file format specifications.. it's a cancer of the Internet.
So, the only options for people using alternative operating systems are..
1) Unreliable Linux/Windows emulation..
2) Alpha-quality reimplementation projects like gnash or swfdec..
3) FLV stream capturers, sites like Youtube have a "flash wrapper" that plays FLV format video streams.. utilities exist to download these streams directly.
I personally have a few additional options..
4) Avoid flash utilizing websites entirely..
5) Submit interoperability reports to tech support staffs...
6) Disown friends/family who send me links to YouTube/Misc Flash content.
In the end, you'll need to decide what's most important.. a stable decent OS.. or Flash.