I personally bought it because it looked like some innovation on the 2D Mario formula, which -to me- had become stale with New Super Mario Bros. The little I played multiplayer, I didn’t find it particularly great, mostly when players have very different level of skill. I think this might be a case of “correlation does not imply causation.” But what do I know 🤷
What’s a safe bet is -as the article says- the movie definitely helped boost sales, as it did with older titles like Mario Kart 8 Deluxe.
Mario 35 was a special game that was only around for Mario’s 35th Anniversary. It was announced from the start as being a limited time only thing, it was actually very popular right up until it closed, just as Nintendo had always announced it would.
I still think they should have kept it around, but its removal was not unexpected.