It’s not free in a literal sense.

I understand the concept. I’m just saying it has consequences (especially longer term) which are not in their favor.

Like being dependent on Facebook.

Yes, but they can easily switch providers or get the water elsewhere and transport it to the office. Apparently with Facebook that’s not an option

It has everything to do with dependence. If you are dependent on 1 traffic source you tend to cater to that traffic source, thus losing your independence.

You are not independent if you require Facebook for traffic and making ends meet. That makes you dependent. On Facebook.