Nope this guy agreed to it in email. It’s over. License didn’t need to transfer since Microsoft bought Mojang, not just specific property of Mojang.
Can you quote the bit of the article which says that? All I can see is that he said "ok, what's your offer?", Carl returned with "€20k", and "in all the confusion someone sent me the money, even though we still didn’t have a contract worked out" - no contract, no license.
Edit: I’m rate limited, but Microsoft doesn’t need a transfer. They bought the entire company. Just like you buying some shares on the stock exchange, except they bought all of the shares in a private transaction. Had they done an asset purchase instead, your point might be valid.
But the terms of that license are unknown - a court may well decide that it did not apply to Microsoft since he didn't sign that contract. And it also means that he did not assign copyright to Mojang or Microsoft which removes that avenue of them claiming they can use it for free.
A court may well consider that becoming a wholly owned subsidiary would violate a license, despite being a distinct legal entity[1][2]. Especially when it's just an implied license with no actual agreed definition on both sides.
[1] Which is similar to what we're seeing with ARM vs Qualcomm and it should be interesting to see how that shakes out.
[2] Mojang into Microsoft sounds like "forward triangular merger" on this page: https://www.faegredrinker.com/en/insights/publications/2003/...
he smartly follows the line you quoted out of context with "and even that they didn't deliver" or something.
so, no contract, an email agreement which was never fullfilled.
man, be happy this guys is a spineless hippie or you would be working overtime and still paying a deal.