Dropbox recently broke (accidentally or intentionally) hosted images/thumbnails from their Paper docs product (which they're quietly but noncommittally killing off) and that was a good wakeup for me to stop trusting hosted storage. And I'm saying this as a former Dropbox engineer of ~6 years who has plenty of free Dropbox storage for life. The brain drain and profitability crunch is real.
Recently bought a 14TB HDD and downloaded my entire Dropbox, Google Photos, and Lightroom photos. Planning to set up an off-site copy as well, and will probably build out a proper NAS within a few years.
Dropbox is just hard to trust. I used to pay for it, until they suddenly decided to shut down the photos app. Then the password app, recently. I don’t expect Apple to shut down Photos any time soon, so I find it easier to trust them with my data