>>280022680Seems common.
But also think about it from the perspective of the mangaka. It's quite possible that they get one hit, and it's the defining financial event of their lives. Retirement, marriage, family, etc all depend on how much they can extract from it.
Of course there are people who can bang out multiple hits. But imagine you're a starving artist who worked for years either on your own failing shit, or as an assistant for pennies.
Can you really blame them for trying maximize the value a bit?
In a perfect world, they could just write the exact story they want, no personal pressure or pressure from their publisher.
But that world certainly does not exist.
So I kind of get why it's such a common pattern.