Fulltime MBA-an expensive Linkedlin group-or not even that?

After receiving torrents of Linkedlin requests from people who I barely know on campus(mostly our senior batch who are now building their social network enmasse), one thing occurred to me that perhaps the only 'core' value of MBA is in the networking-all the other aspects can be profitably replicated.

1. 'Perspective' of all subjects:- Any decent management rotation program does this, as also cross functional training/fast track programs. But these are available only to few, so maybe for others MBA is the only chance to learn these
2. 'There is no alternative to learn' argument states that for some people who cannot juggle a part time MBA with their job, full time MBA is must. I cannot counter that argument
3. Signalling to employers that you are the elite. Again, stellar job performance should achieve this in relevant industries but those seeking to shift industries/get on the fast track may do this. But with the dilution of MBA quality, this signalling may diminish 
4. Networking:-In a good college, most of your peers will be in equivalent roles across functions/industries. MBA allows you to build bonds with future colleagues, friends, investors, employees and(for those lucky few) life partners!

Given the fees of full time MBA, it does seem expensive for merely building bonds and branding yourself. But then, calculating ROI on education is always a tricky thing. Introverts may not build a huge 'network' like others on campus, but then their campus 'reputation' may see them through later. So I think the networking argument seems the only valid reason for the existence of  a full time program,