Most of this is based off of the success of WoT and the millions of dollars they've made.
Most of them are not P2W (just as WoT is not P2W), you just get extra stuff like more money/XP than your average joe who plays for free.
Heck, even BF3 has a F2P style to it now. "Premium accounts" etc.
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Biggest downside to F2P? Terrible communities.