I think the problem with IG is that, for the majority of accounts, the only way to make real money is through doing promos for other IG accounts since you can't post links, and that's a little...schemy. Sure, some companies buy promos, but they're buying them from a small percentage of accounts.
The obvious problem with Facebook is that your posts only show up in the news feeds of 35% of your friends.
To me, personal experience aside and just looking at it from a rational viewpoint, Twitter is hands down the most profitable. Every one of your followers sees your content, you can post links, and you can also monetize through promos like you would with Instagram.
I haven't tried pinterest or tumblr so I don't know about those.