> Is this an actual issue

Yes? I mean, it exists and I know of at least a half dozen people in immediate proximity to me that have kept old devices around in case they want their photos later. Some have them backed up elsewhere as well, sure. Contrary to your assertion, I'd guess the opposite - I suspect there's a large number of people, especially non-technical people, with phones in drawers with information they'd like to have available for "some day." Obviously speculation based on my own experience.

WRT the off device syncing being default, that is fine up to the Xgb that the provider offers free, anything beyond that is not synced without a monthly subscription, and the same people I know that are keeping phones around are also not paying for that.