Hah! Well, I played Twilight:2000 once. Briefly, and once, but yeah... Where was I?
At the risk of being obvious, I don't think the mere fact that someone has lived for X years and played Y games over that time has anything at all to do with the "breadth" of their roleplaying experience. I used to GM at RPG tourneys back in the day. Trust me. There are a zillion players who've played many many RPGs but who I wouldn't trust to put the car in park, let alone consider good roleplayers.
I'd also question whether the sheer number of games one plays at all makes them a good roleplayer, much less a good gamer at all. I know a guy who playtests games as a side job. He's a great guy. Can quote rules from more game systems then I care to count. But he can't stick to any one game system long enough to do more then learn the mechanics half the time. He gets bored quickly and moves on. I suspect that most players who buy a new game system every month or so are similar. Sure, they've got "breadth" of experience, but I've got to question the "depth".
Personally, for me it's more about the game world and the storyline. I've played dozens of game systems over the last 30 years or so, but have probably only spent significant time playing a handful. And of them, RQ has easily been the longest and most often played (yeah. I'll toss a plug out there). Started playing shortly after 1st edition came out, and really have never looked back. The game mechanics of RQ were superior when they came out, and still are equal if not still superior to pretty much any other game on the market (largely because most game systems have adopted concepts that RQ came up with 30 years ago). I've just never been interested at all in playing any other high-fantasy type game in any other system for any length of time. Every time I've tried I end up thinking "Gee. I could simply incorporate this scenario or campaign concept into RQ and it would work better".
Games in other genre's worked great though. Loved champions to death. Really enjoyed Shadowrun (2nd edition of course). Dabbled in Vampire. Um... Probably a few others that I can't think of right now.
Now, if we want to talk about depth and/or campaign length... That's a different story. The current RQ campaign I'm playing in has been running continuously since sometime in 1980 (the originator played a different game world for a year or so before switching to the current one). Players have come and gone (I think there's only 3 of the original left). But the entire campaign has been played in a continuous timeline from a starting point about 28 years go in real time (and I believe 120 years now in game time) and has run straight through. We've had characters start, adventure, retire, grow old and die during this time. Many of them. There are some characters being run today that are the great grandchildren of some of the earliest characters. It's not uncommon to run plot threads in this game that take 3-5 years to play out (real time, so upwards of 15-20 years game time).
There may be a game or two out there that's run a longer single contiguous campaign, but probably not by much. So you can take your breadth all you want. I've enjoyed playing in a game world with a long and rich history, that has survived intact for so long and looks to continue for a long time to come. IMHO, that's why we play roleplaying games, right?