I don't think it is fair that you can't buy pets orpets cause wizards from these schools would like to have a pet from their school without using crowns or earning it.
Do you mean buy from the pet shop? There are some in higher worlds, just not in the Wizard City shop. You will also get some free pets from quests. You can get many kinds of pets from hatching and boss drops too. Crowns are not the only way.