> For example, I think they’d still be able to do the pay once model if they abstracted they storage to work with Dropbox/icloud/OneDrive/whatever.

I get why they don't but I often wish more SaaS companies had a bring your own computer & storage model. It doesn't make sense for 95% of customers and the 5% of us who might like it and have the tech chops to use it would just complain about having to pay more because we are outliers. But I wish it was offered!