This is a very interesting theory, I don't know if this was revealed somehow but considering how consistently terrible the guesses are on assistant devices... I wouldn't be surprised.
I think the far more likely explanation is just that these home assistant products suck.
Assuming the voice recognition part worked perfectly:
1) query song database for input 2) play result that is most popular (most plays by manual selection in eg desktop client etc)
The only tricky part is to determine whether the query is an artist or a title but again in most cases this will be solved by checking popularity.
What's a plausible explanation that they mess this up so badly?
Karaoke time! You can do this.
I am sure they're working on improving it. We've not yet reached late stage capitalism with voice assistants.
Ask for War Pigs? Here’s the live version
Ask for a Come Sail Away? Here’s a terrible cover
Ask for Magic Stick? Here’s an instrumental
I swear it just picks the version of the song that pays the least royalties and plays that instead of the right one...