Maybe but the person's point stands. Facebook has multiple datacenters with probably some kind of backups. It keeps things for years at a time even when it doesn't need to. It likes to because it helps the business model. Hardly anyone's pics and stuff will disappear.

Compare that to their experience at home with personal gear. Many like the convenience and reliability of Facebook over their own technical skills or efforts. You'd have to convince those people... a shitload of people... that they should start handling IT on their own. Also note that there's many good, smart, interesting, and so on people that simply don't do tech. Anyone filtering non-technical or procrastinating people in a service will be throwing out lots of folks whose company they might otherwise enjoy.

So, these kinds of issues are worth exploring when trying to build a better social network.

It only takes one time of having your account locked by facebook or google and said people are automatically convinced of the obvious advantage of being in control of your own data.

Same with backups, lose your data to drive failure or theft once and suddenly having a backup strategy becomes a priority.

But as long as they have not been bitten once they don't care enough to actually do something proactive.

They usually resolve those with access to their data. Their computers getting trashed by malware or breaking is different. It can cost money to do recovery that might give them nothing. That concern is the more common case.