Pretty much. A 4x return is great and all, but MV was likely the best reviewed and most Apple-hyped paid iOS game of the year. To only make 4x return off of it is pretty unfortunate for the platform.
They also got a ton of hate for being a paid game, with their expansion pack it was a total of $6 if I recall. This got them swarmed with a ton of angry people giving them one star reviews. That's very telling of what the mobile game market is like. Also I feel like part of why iOS turned out to be such a large chunk of the revenue is because of the large time gap between iOS and Android release.
They also managed to piss off many of their original customers by charging them for the Forgotten Shores levels. When the original was released, the main menu indicated that there were going to be more levels added in the future. Many people were under the assumption that the $4-5 they'd already spent on the original ten levels would've included the the cost of the additional levels that was advertised in the main menu. It didn't and then ustwogames got upset when they started getting one star reviews for their bait and switch.
In terms of revenue, they would still be making much less if they didn't charge for the expansion. You can see most of the revenue came from the initial release of the original and expansion. If the expansion were given for free it may be more like a 3x gain on their investment. If they added IAP for the new levels, they would probably still get the 1 star reviews.
The development cost didn't separate the ios and android releases, but I agree, it probably would only have been a marginal increase. Doubly unfortunate for android.