Worth remembering that Paul Graham defended the Facebook/Instagram merger as the expected, non-malicious outcome of a healthy startup economy - see under the heading "Understand" in http://www.paulgraham.com/growth.html .

I'm inclined to believe that Paul Graham understands the startup economy well, and therefore that this isn't a problem unique to regulating Facebook, this is a problem that will keep happening, in many ways, if regulators / lawmakers leave the startup economy as it is.