the game has p2w elements for sure but this isn't one of them.
1. you are at gym 5 in Kanto(the first region) even in the regular games(FireRed/ LeafGreen) you wouldn't be able to catch this line yet
2. there is no "paywall" for these spawns as there are multiple other ways to get them which can be reached by simply doing the basic requirement i.e. the storyline.
3. The Pokemon you want (Dragonite) is a pseudo-legendary meaning that it has to be made much harder to obtain than regular pokemon which is why similar pokemon like beldum,Axew, ttar all have limited spawns and aren't easy to find especially when you haven't completed the whole story and unlocked most of what the game has to offer