> so how do we know which platform is “right”?

The right one is the one the original author of the artwork released it on. The thing about NFTs is the connection between digital items and their authors.

If you're like most art collectors you'd follow the author anyway. You'd buy one because you're a fan of the author and enter their nft sales funnel.

This doesn't address the problem either. How do you know which platform the original author released it on? How do you verify who the original author is? The answer: by consulting a trusted external source. Which raises the question, if we're involving a trusted external source, why not just use that source to track the token rather than involve a blockchain? NFTs are a solution in search of a problem.

> if we're involving a trusted external source, why not just use that source to track the token rather than involve a blockchain?

How would this work?

Well, you don't. Things don't have identities, not really, and so all the superstructures built upon such concepts collapse the moment when demonstrating this dirty philosophical secret becomes practical ― and digital entities are perfect for such demonstrations.