id would have to invest money in infrastructure to offset the new waves of players while having to pay steam a cut on every transaction, on the offchance that the broader playerbase would bring in enough profits. that is not likely with a subscription system. free to play has to make its money in other ways
The influx of new players might be exciting. It might also increase complaining ten fold. A friend of mine told me that when TF2 became free the servers were packed with noobs.
Servers are already packed with noobs, the difference being in quake live there's at least some what of a skill matching system so it wouldn't affect it too much
What you need to understand is that the real challenge isn't actually to get a lot of people to try the game (which is moderately easy nowadays) but to get a lot of people to keep playing the game, which means you have to somehow retain those players.
QL is awful at player retention, and I mean AWFUL. There is not a single element of the game which would make a new player come back if he tried the game for the first time. Quake Live is really old fashioned in the sense that the only goal in Quake is to get better. There is nothing else to it, you won't unlock any new weapons, any new skins or any new features if you keep playing the game, the only thing that might happen is that you might get better (because it's not even guaranteed) and it really doesn't seem to be in touch with the current direction of video games.
I hate achievement driven gamers what happened to just having fun playing the game being all the reward you needed? You need incentive to play a video game? How spoiled can today's kids be? Quake needs to look to the older audience since most of its player base is in its 30's by now. Which makes me wonder why get rid of the blood and gore when most of your player base is adults. Bring the dark gothic feeling back to quake. The Blood and gore genre is ruled by zombie shooters. Their is surprisingly a lot of players who would have fun just seeing blood and guts in FFA with death metal playing in the background. This seems like the most logical way for Quake Live to build a player base back up. For the younger quake players Yeah I doubt a mature tag is going to make them stop playing quake. The FFA blood and gore mod gibs and blood spray all over the floors and walls and don't disappear, how much of a bloody mess can you make.
It's cool if you don't like it but it's a developers choice to either appeal to the mass public with experience points and awards OR release a game for people like you. A very limited playerbase, barely anyone playing and no competitions, nothing to keep the game alive and keep the newcomers from staying.
I also don't like the whole "this game has achievements so I don't like it" argument.
You DON'T have to play FOR the achievements, just because it's there it doesn't spoil your fun, it only potentially brings in more players that came for the awards and stayed for the fun.