If Apple were "blocking" Flash and Silverlight simply to preserve their media sales, they would be blocking any kind of streaming media, including HTML 5/ H.264.
Since they are not, it makes more sense that they really don't want any single company to "own" the delivery mechansim, especially if it is buggy, crash prone, or a resource hog.
What matters more - unit share of a market or dollar share of a market? Gross sales or net revenue?
This is exactly the position Nokia is finding itself in in another market - making most of the "units" sold, but getting a tiny share of the profits (if any).
Chasing unit sales at the expense of profitability is a good way to bankrupt a company.
However, IF Adobe made CS4 for Linux, and IF you P2P downloaded it and installed it, you too could have this Trojan on Linux.
Most Open Source downloads offer checksum validation - I wonder how many people actually validate what they download?
I don't believe any company has lost as much money as Apple due to not having proper patents and enforcing them. Microsoft alone built a large part of their business courtesy of Apple's prior ineffective enforcement, from Windows to QuickTime and a lot in between.
The fact is, if Apple had not done multitouch first, they would have nothing to patent.
Since they had the vision, did the R&D, bought a few companies and released an actual product incorporating the technology, it would seem they are entitled to a patent on that work. If there is nothing unique or prior art in the patent, it will not stand anyway.
:Would you buy a Macbook to do some hardcore multichannel audio processing anyway? I know I wouldn't.
You can do this with FireWire, as it is not CPU dependent - trying to do pro av with USB requires turning off all nonessential services, screensavers etc as USB throughput is entirely CPU dependent.
The data flow in FireWire is around the CPU, not through it.