Cause and effect is reversed here. The trends leading to collapse of the family , neighborhoods and friendships predate facebook by at least 40 years. Bowling Alone describes the collapse covering the 80s & 90s, and the trends were 20-30 years mature by then.
IIUC, Bowling Alone pointed the finger at TV. If you looked at time-use surveys in the 50s, versus when Putnam was writing in the late 90s, it looked like TV watching had eaten much of the time that used to be spent doing IRL social activities.
Your theory is that Facebook not only had no impact on that but could have done nothing to improve things?
That seems implausible to me. I think at best you could claim that cause and effect are quite tangled here.