It's definitely a killer in merch and apparently did strong numbers on Netflix.
Though that's a good point: Bob's is not a particularly ambitious show that would go for something like, say live-action or have an epic, special effects heavy plot like The Simpsons Movie, which had a rather slim $75 mil budget. And that, even as the highest-grossing TV adaptation couldn't crack 200 million domestic. I'm imagining Fox greenlit it under the notion that it has a 30 to 50 mil budget. I mean, even if uses something like Toon Boom Harmony, I guess whatever MLP cost will be telling and I doubt it's over 30 mil.
So even if Bob's earns a fairly mediocre $30 mil opening weekend at the box office (easy considering skyrocketing inflation), it will still make a decent chunk of change. I mean, is the show even popular worldwide? I have no clue.