Earlier quoted context omitted.
If the whole world uses DigitalOcean for NFTs sure, but maybe we end up in a world where there are many providers. And not one that controls everything (by which point it's not centralized). Similar to right now many crypto is stored in exchanges but not one exchange holds all.
I can hack into those providers as well, right? My worry was that the chain of trust is broken by definition - as soon as you store things outside the chain. I really don't understand why one would dilute the value proposition of the blockchain like that. If I have a Ferrari I shouldn't put monster truck wheels on it only because it can't drive over speed bumps - it kills the "ferrari-ness".
From the chain perspective they never really leave the chain. They are either locked (most L2 solutions such as Bitcoin Lightning) or they are held by someone else (most centralized custodians, including exchanges). So the worst that can happen is that the locked/held coins get "stolen".