Ok so for a more serious answer, Blumhouse doesn't get to keep all the profits from its films since they don't distribute and I'm unsure if they ever spend P&A dollars either.
Still, they probably are a very successful company, but
they have a model and they stick to it:
1) Not too many speaking parts, as extras are paid five times more if they actually talk.
2) Not too many locations, which stops costs spiraling.
3) Pay actors the bare minimum, but give them a slice of the profits. This means that if the film does well their pay increases, and as such they are more invested.
4) Dont ever go over budget.
Their restraint is honestly maybe the most remarkable thing about them.