All these companies have "fundamental" patents. (Score 4, Insightful)

If Microsoft tries to sue McAfee, Symantec, etc. for violating this patent, they will countersue Microsoft for all the patents they got on fundamental stuff years ago. It just won't happen. What we have is a sort of "old boys network" where they all agree to not sue each other.

The real point of getting patents on these kind of fundamental technologies is to prevent new players (that don't have huge patent portfolios) from entering the market.