you are paying them for their knowledge. i remember when i was a criminal defence lawyer i had a client who was pissed off that i got am aquital in the first hour of trial. the crwon made a major mistake and i was on my hind legs like jack in the box with a motion to dismiss, the judge dismissed the case. the client was pissed that i charged him for the whole day. i informed him i billed by the days in trial and any part of a day in court was a billable day.
i told him well i could have dragged ot out for five days and you get a conviction, then you'd reaqlly get your money's worth.
you pat professionals for the knowledge and education , not for how long they take to do their job. some things are quick to those who know. and for those without the knowledge they could never get a correct result no matter how long they worked at it.