Your mortgage is more complex than it appears. While you typically only deal with your servicer, which takes your payments, credits your account, and forecloses if you default, there's another party involved in your mortgage loan.
This other party, although usually invisible to you, has the biggest stake in your mortgage. I'm talking about the investor. They're the “end user” of your mortgage. They own it and earn a profit from the interest you pay them.
Many homeowners only learn about the existence of an investor in their mortgage when they experience a hardship, can't pay their mortgage, and their servicer tells them that their investor won't allow them to get a loan modification.