For example, you say lawsuits are costly. To a company, that's meaningless. The only question is, is the cost of a lawsuit greater than the money saved cutting corners? If not, it's better to kill people and deal with the lawsuits: [1].
Moreover, companies are still run by people, and people have biases. Most notable of which is the short-term thinking bias that results in companies irrationally optimizing for short-term gains, compromising long-term ones. And what fits perfectly into that trap? Yep, safety. Do you know how much money you could save by delaying maintenance? Lots, lots of money to be had right now vs a nebulous concept of potentially higher chance of an accident at some uncertain point in the future. The monkey with its primitive brain chooses the immediate reward every time.