I'm sure some in bank management look at all of the accounts of people who live paycheck to paycheck, with average daily balances under $1000, and think that they don't need these losers, that the accounts cost more to administer than they actually make from them, at least without all of the additional fees they're trying to pile on. But that's basically most of their customers, and without them they won't be a bank anymore. They need reserves to function.
...and echoing this commenter, when it comes to the bullshit fees it isn't just about the money, although it's of course the money too. It's one more bullshit thing to worry about, to pay attention to, to have to keep track of. People are tired of dealing with crap that is going to take up another hour of your life. It's a complete mystery why people don't want to constantly worry about whether or not their bank is screwing them.
