There are many people who could pull off an attack like that if they were so inclined.
The combination of all three tends to mostly appear in nation states. They have the motive, and they have the money to fund people with the ability to pull off this kind of attack.
Plenty of expired npm maintainer email domains right now. Have fun.
I have done it twice to bring exposure to the issue. Seemingly no one cares enough to do the most basic things like code signing.