O365 was the first thing I was looking for. The university I work for is heavily invested in O365 calendaring and Tasks, but for myself personally I use a combination of other services. If this could bring them all together for my wife and I to have a single pane of glass I'd be in.
We didn't do it so far because our main problem was product-market fit, and increasing the addressable market was secondary.
I agree with everything you said, and thanks for the suggestions!