I mostly agree with this, but I think it's more subtle.
Every game developer I've ever known, which is a good number, was a hard core gamer who loved games. Most of them really reduced it as they get older - not just because as you get older you just don't have the time or energy, but because doing something for work just kind of ruins it for most people.
That last bit is very common: my wife is a professional artist and doing that as her profession has just about ruined her interest in painting and drawing despite doing it for a lifetime. I was a hobby coder my entire life until mid-way through my career. Now although I sometimes do short stints, I gotta say, it is kind of ruined for me.
So, sure, you are probably right, but probably for the wrong reasons.
As for "unproductive hobbies" the reality is that all hobbies are basically unproductive. The stained glass artists I know struggle to give away their output because there's only so much anyone around them wants, but their hobby is to produce it. Ditto the painters, woodworkers, etc. Yes, these can give you practice with useful skills, but they're still basically generating a waste product, and if you try selling it, on average, you're just trying to mitigate your losses, piece work is almost never financially sound. This is all to say that one shouldn't view hobbies as "productive" or not, you should view them as providing benefits not directly related to the activity. Hiking, running, cycling, weightlifting - these are all "unproductive" but they are useful practices. Games aren't devoid of value in this sense - hand eye coordination, rapid tactical thinking, etc. are all skills you develop and maintain with practice.
That said, I'm 100% on board with you about the parasocial relationship thing, but to note the obvious, the real elephant in that particular room is social networking in all of its guises. Video games aren't even close, and, if anything, are probably closer to the "real relationship" end of the spectrum than any other online endeavor. I know many gamer groups who have transitioned to real life on multiple dimensions, far more than "hey these are the people i interacted with on Twitter" and other purely ephemeral constructs.