A sensible outcome if communication and other network losses from lack of co-location outweigh the costs of high peak transportation requirements and the costs of those being under-provisioned.
Which was probably very true in the past, and while changing is probably still true.
Because the capital owners have externalized the cost of transportation to work onto labor. They don't pay you to sit in traffic so they don't care how efficient it is.
Granted, but maybe the most curious thing about it is less the outcome than the mechanism -- there's apparently not an aggregately negotiated process that's market-like for arriving at the schedule for an organization.
I suppose I can imagine that perhaps at some point maybe there was a diversity of choices, and perhaps some critical plurality settled around 9-5 external facing availability, and once that happened, others that did the same had an inter-firm communication efficiency advantage, leading to wide adoption, but that's a just-so story rather than a studied opinion. Anyone know the actual history?
And that's a more macro scale. Internally, one presumes that either:
* It doesn't occur to most management to think about different ways of doing scheduling at all
* They've thought about it and it seems that the cost of aggregating an adaptive schedule is larger than the cost of dictating one (especially if most of the latter costs can truly be externalized!)
* Real day-to-day and career incentives for management reward 9-5 schedules
The managers want everything run on their schedule so they can keep an eye on things. That is the process, for better or worse.
I've worked at two or three startups (and heard of others) where, when it was time to move to bigger offices, there was a long discussion about moving the company out to the suburbs. Everyone hired on because the job was downtown, except who? Management. Now that we're doing well they want to make their lives easier. It came to some very angry conversations and threats of quitting before they would relent.
If memory serves, none of these individuals were of the facilitator school of thought, where the manager's job is to make sure everything is running smoothly.
Which was probably very true in the past, and while changing is probably still true.