The funny thing is that whoever jumps first in this battle will lose.
For example, if Activision suddenly "tolls" its servers, everyone will shift to an EA game -- and EA will note that it is free. (EA does have a one-time charge for an on-line passport for second-owners, but most people actually understand that).
The sales of the Activision game would tank - and it would have a difficult time making as much money under its new model as under its old one.
New MMOs can charge because they almost all do so -- and the ones that don't are often riddled with bugs and worse or are just plain bad or unfair.
But unless all publishers acted together -- which would be illegal under anti-trust statues in most nations -- unilateral action in this direction is destined to failure.
Mike from Morgantown