The cashshop is
just another way to milk the cow without abandoning the
steady income which i think most people forget is the actual reason why we get so much "new" stuff over the course of a year: because devs can plan ahead due to subscription numbers
And yes, of course they want to keep you playing, because that is how they make their salaries. Less Money equals less going into development,less resources to develop, less customers that yearn for the NEW NEW NEW NEW NEW NEW NEW NEW and come back for 1-2 month for every patch.
But f2p tries to suck every penny out of your purse with methods that are more then questionable if you think about it for just one second:
...
minions and mounts (now dont come and say "WE GOT THAT NAOW TOO CRY SOB MIMIMI" - we got 1 mount in the shop and, how many of 120+ minions?) that are usually gated behind an absurd rng wall that can only be called a casino
Equipment equally to drops in highest level raids bought for a couple bucks
Instance reset items - you want to do something more then once a day - well to bad, you better pay up then
etc etc etc etc
tl;dr:
f2p is in for the quick buck - and the game will usually die off into only a few server after 1-3 years
p2p is in for the long run - the game usually has a growth curve and a decline curve with spikes on patch and expansion dates
I for my part will quit this game if it goes f2p and i dont like the shop methods/changes - same as i quit AION/RIFT/TERA those games are still up and running, but to see how bloodsucking development becomes after a game goes f2p is horrible :/