I was married to a lawyer for years. They have to bill somewhere from 1700-2200 hours a year to stay on partner track. And they can’t bill every hour that they’re working (although they can double up sometimes by using the minimum 2/10ths of an hour). My sympathy is with the lawyer. It’s not a power dynamic, it’s how the firm makes money and what you’re there to do.
Because their continued employment depends on them hitting their targets so they need support staff to do their jobs.