The reason dragons are rare is not that they have few young. They often have plenty, it is just that very few survive to adulthood. Many die due to their innate arrogance, attacking things they shouldn't tackle yet like towns or groups of adventurers.

And then there are other dragons. Dragons, particularly evil ones, are highly territorial. A smaller dragon showing up in an larger's domain is often viewed as a meal conveniently shaped for easy swallowing. As with snakes, one dragon fits neatly inside another.

The fact that the dragon they want to eat is the same color is no barrier. That just means that the predator will be resistant or immune to its meal's breath weapon.

In extreme cases a clutch of youngsters has its numbers quickly whittled down as half of the dragons end up inside the other half. And then perhaps even further as the hungriest digest their relatives and look for another meal.

The result of all this is that most dragons avoid the company of other dragons, not because they are antisocial, but because they'd rather not hear a dragon burp from inside that dragon. This is much less common with "good" dragons like Golds, but it's best not to take chances.

I drew an earlier version of this at BLFC but it had some real problems, so I drew a new one today. I'm just about over Covid so I can get back to drawing.