Re: Almost, but not quite, entirely unlike Outlook
What in your proposed solution actually centralizes the calendaring? And does all of this work on iPhones? Android? Mac? Windows? How much setup does it require per user? How fragile is it, both from a client side and from a server side?
This isn't just "a cultural issue". This is "a usability issue".
The issue around this is that what people want is the ability to walk into a car dealership, sign some papers, then turn a key and drive away with a car. They don't want to go to a parts shop, a machine shop, a metal shop and then to a hackerspace to assemble it all and ultimately end up with a car that can only drive 4 out of 7 days a week and can't make left turns.
What the open source crowd don't seem to understand is usability. With Outlook, my users can enter their e-mail address and password and that is all they need to enter. That's all that I, as an end user, need to enter. Everything else is handled through DNS and the client/server relationship.
One username and password gets calendaring, mail, contacts, distribution lists, public folders and more. Do you understand this? One user name and password. One application. One thing to troubleshoot. One application to learn. One application to teach.
No setting up multiple IMAP accounts. No downloading 5 different add-ons, only one of which is commercially supported, and two of which are no longer maintained at all.
At least the LibreOffice people have grokked that bundling and usability are important. They have figured out that any collection of interconnecting applications that important has to be maintained as a unit, so that no one piece falling behind (or being abandoned) threatens the whole.
But the mail nerds never get this. They seem perfectly happy with maintaining a spider's web or barely-compatible version-unbound components working in loose formation, and then going back every few years and reinventing the wheel.
I don't know about you, but I'm tired of reinventing the wheel. I just want the goddamned thing to work. I want it to work today. I want it to work tomorrow. And I want it to work 10 years from now.
E-mail is e-mail. Let's please just STOP FUCKING WITH IT. Let's stop having to reinvent, reconfigure, tweak, change, adapt, learn, relearn, teach, modify and change. Let's just get it right and then leave it the hell alone.
Computers are here to make our lives easier. Not endlessly faff around with in some insane attempt to be "more efficient" through constant - but ultimately useless and unproductive - change.
Show me an exact stack of applications - server and client - that replace Exchange and Outlook without having to retrain everyone, or redo every few years, or have a half dozen sign ins per user per device, and I'll be thrilled. I hate Microsoft in the gor'ram face. But a fist full of monkeys that all have to be carefully thrown in the right barrels is quite definitively also not the way.