When Does A Car Become Rare?

In my household, we recently acquired another vehicle due to an increase in drivers. The vehicle selected was a 2004 Hyundai Elantra. I quickly started noticing these cars when I see them, whereas before, I kept forgetting they existed. Such is the case with cars that the press often overlooks and buyers pass over. What I've noticed is that relatively few of these cars are on the roads around here. Now, with over 100,000 sold in the US during 2004 alone, it's not really a rare car.But regionally, they are not in large supply.Which got me thinking, "when is a car considered rare"?
A second occurance boosted this curiosity. I spotted a a late-90s Mercury Cougar.Once quite common, these cars have reached the age where they are being junked in large numbers, but aren't yet considered rare.
Honestly, I'm not sure what to consider such cars. Our Elantra is not a limited-production car, but in rural areas and the midwest, they are not exactly common like Impalas and Fusions are.Some Asian cars are often seen in the coastal states but not places like Wisconsin. Is a car still rare if its rarity is only regional?
Likewise, when do older cars become rare? Sometimes it's hard to tell when the model is still produced. A 1984 Honda Accord and 2004 version are the same model, but different in many ways. Newer Accords are a dime a dozen in cities and suburbs, but in many areas, previous generations range from rare to non-existant. Nobody thinks of  the final Buick Skylarks or Toyota Tercels as rare, but they are dying off and surely in some areas, they may exist in scant numbers.
For the record, classic cars do not apply to this question. They are in their own class. Of course 1970s Firebids are less common than Pontiacs from 2004, and chances are there arent 4 or 5 driving around the same town at any given time, but they would not be are by classic car standards.For sure, they have survived in greater numbers than Pontiac Venturas from the same decade.My thoughts apply mostly to cars no more than 15 years old.Cars either old enough to be taken off the road en masse but still new enough where many are still in service, or cars built in fairly good numbers but that often only found regional success.
There is a 3rd part, too. Obscure cars that never sold well but are still pretty recent. A good example is the Suzuki Forenza. Few bought them, but they are still new enough where attrition hasn't forced them all into retirement yet. Can owners consider them "rare", or just "obscure"?
As for our Hyundai, we didn't buy it as an investment. Its for basic commuting. Not seeing many around here sort of makes it more enjoyable to own, since we have don't have the same car every other person does.It's just an observation that I wonder about.Maybe the term "rare" changes definition from person to person. Maybe it's much harder to guage than many of us realize.Regardless, its a question worth pondering if we own cars that could potentially fit into that category.