Amazon doesn't sell digital music; they sell a license that contractually they can revoke at any time.

It's possible that Anthropic also structured its EULA such that we're buying Claude Fun-Bucks with no value and that they can obliterate at any time with no recourse. I haven't read the EULA so who knows. But if they did this and it went to court, they'd still need to get a jury to agree to this interpretation and that's a huge unknown.