The laugh of it is that Prototype 2 hit the top of the US charts in April.
Doesn't matter. The question is, did they make any money?
There's no point in blaming Activision if they were not making money.
There is if Activision was taking the lion's share of profits, if they can't make payroll then Activision is a bunch of assholes (signed, lopsided contract notwithstanding).
Radical Entertainment was a mediocre developer at best. I get the feeling people would feel a lot less compassion if they couldn't blame Activision along the way. http://en.wikipedia.org/wiki/Radical_Entertainment#Games_developed
They had a few decent games, but the bulk of their work was nothing really interesting.
Prototype was amazing, seriously, it was like nothing I'd ever played when it came out. I can see why some people might not like that kind of game but I refer you to this: http://www.penny-arcade.com/comic/2009/6/19
Prototype is filled with that level of awesome.