Lol.
Nice idea tho. But, I think, it is not about why Pc tools does not wnt to make it, maybe it is more about why does PC TOols have to make it that way?
Onguard may consume lots of memory, but, i dun really have that kind of problems. and now they have Int. Security. eventho everyhting (onguard etc etc) is ON, it runs so smooth like SILK.

Thats why I like Internt security so much. lol.
now, you may try to think, "Why they have to follow your idea?". Try to put your self in their position. what are the advantages and what are the disadvantages. At the end you should know why....