This is one of those situations were worse is better.
> Google and microsoft of course may do some non-standard futzing around within their proprietary stacks: you can often see these problems when you try to connect to something outside their silos, though in my experience the standards integration in google calendaring is pretty good (especially when compared to their mail system).
Yes, crossing the two is often still a hot mess.
The first paragraph sounds great in theory. The second paragraph sounds more like what happens in practice...
Sadly, in this particular case, I can forgive them. The fact that iCalendar is the best we have is sad. There is a lot of room for improvement.
https://kristiandupont.medium.com/the-sad-state-of-webcal-d8...
There's an open standard, icalendar (https://icalendar.org/) which represents calendar entries. Invitations you get in the mail come this format too. The easiest way for your map, address book, reminders etc to integrate is just to talk to your calendar server. The apps need not know about each other at all.
Google and microsoft of course may do some non-standard futzing around within their proprietary stacks: you can often see these problems when you try to connect to something outside their silos, though in my experience the standards integration in google calendaring is pretty good (especially when compared to their mail system). It's been a few years since I had to interface with Exchange calendaring but back then it...wasn't good.
So in any case there's no reason you couldn't write a small service that spoke ical over the network and this plain text calendar's format locally. Then it would appear normally in your partner's iphone, handle your kids' schools' calendars etc.
Whether it would be worth doing that is literally an exercise for the reader...but you'd get the same level of integration as you would with, say, Apple's icloud calendar services.