Just like you I thought this was a solved problem, but when I wanted to try it in pactice, I ran into two issues with this: 1) The calendar subscriptions aren'

Just like you I thought this was a solved problem, but when I wanted to try it in pactice, I ran into two issues with this: 1) The calendar subscriptions aren't read/write, they are read only for subscribers. You can't share calendars between Google and iCloud read/write. 2) Android apparently doesn't support CalDAV! I tried, but I couldn't get an iCloud published calendar to show on an Android phone, not even read only. The only way that I managed to use a shared calendar between iPhone and Android was to use a Google account on both phones.