This issue alone really makes me question whether they ever even played dnd. Dragons are end game encounters not trash mobs
Have you ever played DnD? Dragons Endgame encounters?! Don't make me laugh.
Ancient Dragons are around CR20. Even that isn't endgame content alone. (Well maybe in BG3 if they have a level cap at around 10)
Adult Dragons are around CR15. This is something I'd pit against a party of around level 6-10.
Young Dragons are around CR10, and perfect bosses for parties of level 3-5.
Wyrmlings are around CR5 and not uncommon to encounter at lvl 1 or 2. (Even in official DnD Modules)
So no, Dragons aren't supposed to be a rare thing you only fight at the end of the game. The game is called Dungeons and DRAGONS, you are meant to encounter dragons.