Having more than one calender app is very problematic to me. My life maps only to one real calendar. And since my employer is dictating Outlook for my work life, I am stuck with it for the rest also. I would love to use other solutions though (have looked into calcurse and remind so far) but the hassle of importing/exporting/syncing with other calendar implementations is not worth the effort and has never really worked for me.
The greatest gift Palm's WebOS gave us was the unified calendar (and the greatest curse was those ads with the lady on the rock). I agree that having too many calendars is problematic, but I think a handful of calendars, shown together, and shared as necessary, is the answer. I also am troubled by putting personal stuff on a work calendar, because I think that's a line that should be rarely, if ever, crossed. If you were unsatisfied with your employer and interviewing, would you put interviews on your work calendar?
Another commenter mentioned it, and I agree, there is something to running a calendar server of one's own, if one is capable of doing it. I've been trying to scratch this itch for years to little success, but feel like it gets closer all the time. Things like NextCloud make it even easier still, but lack the way I want to deal with groupware (service accounts). I'm hopeful that Apple Family Sharing can solve some of this for me and my partner as we both use iCloud calendars today, but haven't set it up yet.
Over all, I agree, and wish I knew the answer, but I don't.
Android does have a unified calendar that every app push into.
It has two problems (that are both dealbreakers to me): it's not easy to make it push the complete schedule into any other calendar (if it's possible at all, I never managed to), and the apps are often not reliable (probably because they don't want to allow a centralized calendar, the MS ones are serious offenders here).
I agree with your overall sentiments in this matter. I am planning to setup a NextCloud server since I have a synology NAS that is under utilized. Partnering that with an RPi running CF Argo Tunnels would securely get it remotely accessible. SO..... I am just lazy.
EDIT: lazy mostly because of the hassle of importing data from my work Google Calendar, and my Apple personal/family calendars.
I feel you, but to me it was worth the effort and now I have a setup that works.
I run a calendar server[0] that is my main calendar repository. And I use vdirsyncer[1] to sync to my laptop to use khal[3]. On the Android side I sync with davx5[4].
This allows me to subscribe to webcal calendars, which outlook365 offers, and syncs them to my two main devices.
Not perfect because that means I can't edit my outlook calendar from within this system ( and a reminder why open standards and interoperability are important ), but it means that my private calendars and addressbooks are self hosted.
You are right though, that takes effort. And I want to snark at microsoft for not supporting caldav, but then I am waiting for gnome-calendar to support it as well. It doesn't seme to and that feels a bit strange to me.
However, according to this issue calendars work once added but the only GUI-way to add them right now still seems to be Evolution, after which they will show up in gnome-calendar as well (also some workarounds here):
This is my setup, but additiinal I use davmail to get exchange support. Only problem is that right now importing events into outlook automatically sends mails to all participants.
Had some FUBAR situations where vdirsyncer tried to fix "something" (which is necessary from time to time since davmail does only rudimentary checks of events) and got im a situation where I send confirmations for 5 year old events to a few dozend people
Exchange has an API that could be used for syncronising. I always wanted to build this into vdirsyncer [1] (so that I can use khal with my work Office 365 account) but haven't found the time.
I use Davmail to talk to O365 and present standard interfaces like imap/caldav/smtp/etc and then use vdirsyncer to pull down my work calender to use with khal. It works pretty good for me, especially now that Davmail does MFA internally so no account changes are needed in O365
If you use iOS/macOS, FantastiCAL brings my SSO Outlook and my personal Google calendar together very neatly. The only thing that bugs me about it is setting up meetings at work, I still need to route through Outlook directly - but all other integrations work well.
Since I'm an IC and never ever schedule meetings unless I really must, this hasn't been much of a pain for me.
