My fantasy explanation is that the form feeds directly into a printer, and they have a guy who takes the printouts, staples them, and puts them in a box. If the website is open 24/7 then when Stapleman shows up to work Monday morning the backlog might be discouraging. Not to mention if the printer jams during off hours and nobody's there to notice, filings may be lost. Or maybe I'm overthinking this.
Your fantasy explanation is way, way off the mark. Nothing is feeding into a hopper from a printer. It is just a huge mainframe that does many, many things for hundreds of millions of individual taxpayers as well as millions upon millions of businesses and other entity types.
[Is break over yet?]
I'm not sure if the IRS is trending towards a paperless office or not (is that even still a thing?), but triggering a print job for every form submitted via a web portal sounds very wasteful. I'd hope they have have some sort of workflow system in place instead.
It's a government worker union thing. They don't have a contract for being called at 4am when the website breaks, so you better shut it off at 5pm.
If you think this is the stupidest thing in government you should ensure you never have to work in that environment over your lifetime :)
Most likely: they don't have anyone on call outside those hours for breakages, so they only turn the system on during working hours.
edit: Another comment linked to a good explanation as to why the site isn't up 24/7. TL;DR legacy COBOL that everyone is terrified of touching. Just in case the Secretary of Treasury is reading this: I, for one, would gladly have my tax dollars go to modernizing irs.gov. Oh wait, I just remembered healthcare.gov. Nevermind.
Source: https://www.washingtonpost.com/news/fact-checker/wp/2013/10/...
Far more has been spent on Facebook and Twitter (for example), and they don't do anything nearly as important as providing health care coverage to people.
Even support chats it annoys me - support open Mon-Fri 9-5 - fine, but can you not just take my message and let's do it over email, or send me a reminder in opening hours with a link that automatically starts a chat with the request I type out now?
It was the Student Information System that we used to register for classes, pay tuition, update our contact information, etc. So it was a pretty important system.
One day, I asked someone who would know. I was told that it was because SIS ran on an old mainframe that couldn't read and write the disk at the same time. So it made all changes in memory during the operating hours, and then it shut down and wrote out the disk at night.
(also, our username for SIS was our full SSN... and the password they assigned to us was the last four digits of our SSN)
That's how it goes for banks, anyways...
All those agreeable office workers and higher class people can access the site whenever (including work). All the icky people working in factories, services or places you sweat don't need govt. services anyways.