Earlier quoted context omitted.
> Seriously, it could be done [...] in a bit of Perl or Python [...] A few hours [...] People said the same thing when dropbox was announced, look where we are now: very few people do it locally, and dropbox has won.
Dropbox has won? Won what? Was there an International File Sync and Sharing Software Competition? How is that relevant to the issue of giving a third-party access to ALL OF YOUR EMAIL for the sake of convenience? How does that justify doing so rather than developing a client-side, FOSS solution?
It turns out that Dropbox has set the standard for how to store files on the cloud and sync them for the masses. My gut tells me they're losing grounds to the GDrive/OneDrive/iCloud et al but it's still a default option for many people. In that sense, they have "won" this domain.
Now, don't mistake me: Dropbox and the likes have created a huge problem with data privacy. But as FOSS developers, we must not think that somehow Dropbox doesn't exist or doesn't solve a problem; if we want a better, FOSS alternative, we must set the bar at least as high, and not blind ourselves.