When will the change happen then you might ask. Very simple. If the largest destinations like fb/twitter and others start to drop v4.
Agreed, IPv4 will be here a long time, because, not one company will risk financial loses and stock devaluation over address space. The day that a large company flips to IPv6 only in an IPv4 world will be the day to short as many shares of that stock as possible. This creates the big market for IPv4. Costs price per IP address must get beyond the price of a good lunch once per month. Because, that's an amount that businesses understand and begin to pay attention. IPv4 address space is now a profit center and will cost more to the end user than transit and network costs... Or... how will IPv6 catch on in any other way ?