Some will blame the new introduction system... but I suspect it's more than that. It's easier to blame it on the changes in the game than to look in ourselves for answers. I hear complains about how the game is not the same and how the good old days were better all the time and it's hard not to agree sometimes. But I wonder, what makes players really stop wanting to RP or need to take a break from it for a while?
Lost friends. People come and go and sometimes it's those who made RP so much fun for us the ones to leave. Seeing one's buddy list all red is depressing. I've experienced that and I understand it can be a big barrier. You know you can't "replace" your old friends with new ones and those plots you had way back sound like will never be surpassed by anything the present has to offer. So why bother, right?
Lost mechs. Mechanics evolve and sometimes that displeases those who are happy with the way things are. One of the things that has been changed a few times along the way, and is more likely to be changed than others in the future, is the dueling system. Some people love it, others hate it and when it is changed it springs a ton of complains. Some people don't want to do anything with PS until it is changed back, not considering that it is only a part of the game and one that is meant to evolve. The correlation between the introduction or modification of mechanics in game and the motivation to RP is direct. I wonder if this is about
Lost skills. Wipes and wipe threa(d/t)s always bring out the "I'm outta here" line. People have dedicated countless hours to training and when they fear their characters might be deleted they don't feel motivated to stay and start over and that means RP was never their priority. They would rather leave than start over.
Lost plots. It is common to see newcomers put together imaginative plots that... well, have nothing to do with PS. Vampires, werewolves, blaster rifles, Jedi powers, etc... and the community is very quick and ruthless when they deal with this issues and that makes the newcomers feel rejected and exposed and they don't wish to stay anymore or try again.
Lost interest in the game. RL makes us do other things, like... living, for instance. We may love PS but when we have to do other things, we gotta log out and do them and that means leaving the game for a couple of days, weeks, months or years. Coming back after that can be challenge. Oftentimes it makes you face all of the above issues so reconnecting with the game is much more difficult. You have to work harder at it to make new friends, train new skills, learn the new mechanics, pick up your old plots, etc and it can make you lose the drive to go in-game anymore and role play.
There may be other reasons why players stop roleplaying but I think these are the most common ones. However, are they valid in terms of role play? They are valid reasons since they do exist and they do affect how players feel about the game but... how much do they really have to do with roleplaying?
Do you stop roleplaying because the community is bad at it?
Do you stop roleplaying because the game has little to do with it?
Do you stop roleplaying because you don't know how to do it and there's nobody to learn from?
Do you stop roleplaying because the settings are boring and unappealing for you?
Or,
do you stop because of the reasons stated in the first part of this post?
I guess the real questions are:
What makes you want to role play?
and
How good at it are you?
If you really love RP, don't let peripheral things get in your way. The game is in development. Be flexible and ready to change as the game evolves and you will enjoy it much more. Complain, suggest, get involved but don't stop roleplaying if you really like it because that way you're only denying yourself some good fun.