Back then, most jobs were manually done; hence the need for those long hours.
According to aMicrosoftwork trend report, the 9-to-5 workday is well on its way to extinction.
Thankfully, technology has aided this transition to remote work.

They were more or less human machines.
But there is a middle ground to be found, which will end the 9-to-5."
He then further stated that “ideas such as driverless cars and more advanced drones are becoming a reality.

Machines will be used for more and more jobs in the future.”
So, employees no longer have to be onsite for eight hours every day to keep workflow going.