Many wargamers get into a single system and stay there. That is evident by how people keep complaining about GW price hikes every year, yet those complainants happen while they are buying the next new release. Of course, the hobby does have a semi-high reentry point every time you jump games unless you can get good proxies (Kings of War/Warhammer Fantasy and Warpath/40K) or the rules somehow furnish you with templates to play with (Firestorm Armada), so can't blame anyone for not wanting to jump ship.
However, when it comes to calling yourself an experienced wargamer or a veteran wargamer... That is much harder, and you find them to be far rarer. They guy who has only played 40K for the last 20 years is certainly an experienced 40K player, but not experienced in the wargaming hobby as a whole. The truly experienced tabletop player is the guy who has played, or still is playing, 40K, Infinity, Warpath, Heavy Gear Arena, WarmaHordes, and Hell Dorado.
I am not saying you need to play every single tabletop game out there, as that is a fruitless battle, but to consider yourself truly experienced in the hobby you should have gotten a taste of other systems. That taste lets you see what other systems do better or worse than your preferred system (which I believe everyone is going to have 1-2 systems they prefer over others).
When it comes down to it, I think a far better scale for measuring a wargamer is on their experience with the hobby as a whole, not simply on if they are or are not a wargamer. Having painted miniatures or not won't suddenly make you favorable with the dice gods, and the tournament minded players have just as much right to play the games or their choices as the casual anti-tournament crowd does. In the end none of that really matters when you compared players background.
Here is what I think a better scale would be.
- Novice Wargamer: The gamer who plays with mostly proxies of a single system, and may or may not even own the core rules. These are the people just getting into the wargaming scene for the most part, or simply want to pay as little as possible. Questionable if they will stay with the hobby at all.
- Intermediate Focused: The Intermediate Focused wargamer is the wargamer who only has 1-2 armies, with few proxies,the rule system of a single gaming system, and have only been playing for a couple years at most.
- Intermediate Spread: The Wargamer who has tried 1-2 various wargames, but never fully invests in those games outside his primary choice.
- Experienced Focused: These Wargamers have been playing 1-2 systems for years. They are very knowledgeable of those particular systems, but have not seen much in the way of what other systems have to offer. While they might have played a game or two of another system during that time, they didn't care for it because it was too different from what they were used to. They tend to try and recruit players into their game specifically, rather than the hobby as a whole.
- Experienced Spread: This wargamer has hopped between many systems over the years, collecting armies, rulebooks, terrain, ect that belong to each system. They can give you a good conversation about their opinions on what the strengths and weaknesses of each system is. May have remained focused on only sci-fi, fantasy, or historicals, but played many systems within that category. These gamers tend to recruit for their preferred genre rather than a single game system.
- Veteran: This wargamer is the gamer who has played all three variants wargaming has to offer, with multiple systems in each system. They can recall systems that no long exist, can weigh in on every aspect of the hobby equally, and tend to be recruiters for the hobby as a whole.
Granted, the scale is is not 100%, but the general idea is there. Most players tend to stay in the X focused areas of the wargaming hobby, which still makes them wargamers to me, but certainly will stop their advancement towards being truly experienced or veteran's within the hobby.
I freely admit, that in my many years of wargaming, I haven't even bothered looking at historical wargames since it does not really appeal to me personally. I accept that I won't ever be able to truly talk about those system, and thus can never be a true veteran of the wargaming hobby.
I hate applying labels to other players, but it is natural for humanity to do. We are always going to look at our fellow gamers and gauge just how much we can take their word for. People will always err towards the person with the collected force and own book over the person used a bar of soap for a tank and borrowed the stores copy of the rulebook for the game.