Resistances are just one form of buff though. Given that all the resistances were addressed in 2.0, it’s not like older creatures were given worse resistances. It’s still a valid way to give out buffs, but the main problem of power creep is more general than just resistances.
Power creep is an odd problem to deal with. Some dinos do need buffs (to resistances or otherwise) to keep up. We want as many dinos as possible to stay relevant, and ultimately we need buffs to accomplish that. But if you don’t address the top-meta dinos, the bar keeps moving up, and the power creep continues: you’ll just have to keep making changes. So some nerfs at the top are neccesary to keep them in check. Plus, nerfing one dino is often way more efficient than buffing dozens, and “dangerous” since every balance change is a chance for Ludia to mess up.
I would also draw a distinction between meta relevant and meta defining. A dino can be used a lot because it’s a solid choice, and that’s fine - no nerfs needed there. But there’s an important difference between them and dinos you’re practically required to run in order to be successful in your arena.