The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
That's what he was asking for, a mention in the credits.
It would be common decency to donate even a small portion of that $500 million, even if the license technically doesn’t require it.
It means there’s lots of info on the internet explaining how to use the license and they can be relatively certain they won’t accidentally fall into some legal trap or misinterpret the license. It also means there’s legal precedent around the license.
All that to say, custom licenses are actually a big issue for small players.