Actually deleting the account doesn't matter -- if you don't use the account, that's what matters more and here's why.
Facebook's revenue is almost exclusively from advertising. Advertising costs on Facebook depend on reach, PPM, and/or PPC. Facebook advertisers don't pay for "active users" or even "users" -- they pay for PPM/PPC. In other words, your data is relatively worthless if you aren't around to be targeted based upon it.
Despite having a profile, if a user isn't there to see the ads, that means less reach and fewer clicks. When advertisers realize the apparent ineffectiveness of FB advertising, ad rates will decline, reducing revenues for FB. It's unlikely FB would actually run out of money because with reduced scale comes reduced costs -- eventually the entire platform might be operated by Zuckerberg at at a WeWork rented desk after having laid off everyone else.
My point is that your data is pretty much useless if you aren't there to be exploited because of it.
Facebook and Google are huge really for one main reason -- self-service advertising. Some local bike shop can experiment with $200 in PPC super-easily. That local bike shop can't as easily run a radio ad or TV ad and measure the results as easily. So Google and FB have made advertising something that is accessible to those with both lower budgets and lower sophistication. The Coca Colas and General Motors of the world don't care about FB or Google at all -- they have the resources to sponsor the Olympics or national TV shows or pro baseball teams.
Technically that is correct, but I don't really agree in reality. Most users lack the discipline to simply walk away from a still available account when Facebook is a savage drug addiction for so many people.
I downloaded my Facebook archive this weekend and it was a massive 12kb. I know entirely what it means to have a living account and not feed the beast, but I am also the rarest exception that disproves the norm. Deleting a Facebook account means the drug addict cannot relapse.
