I'm finding the opposite, it seems to be more with players who had exposure to previous editions. The younger folks I've gamed with don't seem to have any expectations. I've actually seen several friends I've known for 10 or 20 years move to this type of play style, and if they are regular MMO players, the problem gets far, far worse.
Ahh... that. I'm not sure it is what you think it is.
It been true for me that in general, the more experienced the player is, the worse that they are at RPing. It's the only hobby I know where skill on average tends to go down with time, and greater devotion to the hobby seems to go with reduced devotion to the craft.
I don't know what to do about it. I don't know if the problem is that there really is some legitimacy to the idea that playing RPG's as an adult is a sign of poor maturation or socialization, or if the problem is that the gaming experience trains into the player the wrong habits, or if older gamers are more often to have gaming baggage from being burned, or if it's just adults just get worse and worse at games of make believe over time, or if these people are still playing out of habit despite the fact the game is no longer engaging too them, but it's really annoying. In general, some of the most beautifully done RP comes from players under the age of 18. The tend to play their characters. They tend to pay attention. They tend to imagine the environment and interact with it. They tend to actually role-play. They tend to have the expectation that they are their to entertain others as they entertain themselves. They tend to work together (unless their characters really wouldn't). They are creative (though, sometimes, maybe too creative).
Older more experienced players tend to just plug into the rules and interact primarily with the rules. They are more likely to metagame. They are more likely to cheat. It's not having new players or 'munchkins' (in the classic definition of a younger player) that I worry about, but having older more experienced ones.
I don't think you can blame MMO's for anything except perhaps the short attention span. Particularly if they are a long time MMO player, most MMO's put a very very high premium on cooperative end game play, were everyone has to engage in the complex dance or the whole party wipes. And MMO's themselves have tended over time to experience the same problem you are observing, with fewer and fewer percentages of the player base willing to put up with cooperation being required between large groups or tactical problems requiring high degrees of skill over long periods of time.
Of course, I complain but my current group of older players - despite not yet proving to be dogs that can learn new tricks - isn't all bad. The campaign has gone on for longer than any prior campaign I've ran (although, since its 4 hours every 8 weeks rather than 8 hours a week, I'm not sure it's the most time ever in a campaign). I think people are looking forward to it, and there hasn't been a lot of table drama.
I don't have a solution for you, except that I think the 'bug' is likely to be somewhere other than where you are looking for it. It could be boredom has set in, and you need to shake things up to draw interest back to the game. And I think you need to question whether you need to just jump off and adapt to a new edition just because there is a new edition. I'm still playing what is largely 3.0e, having decided that though 3e was a big upgrade from 1e that fixed many of my problems with that edition (and made a lot of new ones) that the editions since then are less huge improvements. I think I could get into 5e, but don't see a need for it for at least 4-5 more years, by which time I may be so set in my ways that I can't change anyway. (Gping back to DMing 1e after 13 years DMing 3e proved to be a huge mental challenge, and rather unsatisfying.)
