If you don't want people to sell their Bitshares then how will they get the necessary ROI?
A lot of money and time goes into acquiring Bitshares. I've heard stories of people spending $20,000 on mining in the cloud just to get PTS so they could get Bitshares and that was back when it could be mined. Now you have Angelshares which cannot be mined at all so when these people get Bitshares how are they going to get back the Bitcoin donations they put into it?
Once the initial ROI is made I don't see any reasonable person selling when they know it's worth at least $1000 a share. But before it can reach $1000 a share you first have to have ATMs and other businesses set up to bring XBT and BTS to the mainstream. The Bitshares ATM will be critical. A fiat to BTS exchange will also be critical.
Unlike Mastercoin and Counterparty, Bitshares cannot rely on the Bitcoin establishment for support. The Bitshares community is going to have to independently build it's own exchanges, its own ATMs, it's own paper wallet generators, and more. PiperWallet and Trezor will have to be modified to support Bitshares.
It is only when Bitshares can be securely stored, easily purchased, and made simple to understand for the masses will it reach $1000 a share. If people cannot figure out how to buy Bitshares or BitUSD, if you cannot get commercial businesses to take BitUSD seriously, and if you don't make it secure and simple, you don't deserve $1000 a share. But if you can do that then it's absolutely worth that.
Initially it will probably be $100 a share assuming Bitcoin is $1000. If Bitcoin goes up because most people can only buy Bitshares through Bitcoin it can reach $1000 a share if Bitcoin is in one of it's bubbles but if you want Bitshares to reach $1000 a share independently and stay there then you need to build value around the Bitshares network.
It's not enough to just launch DACs and theoretical experiments. If you want to see these share prices it's time to discuss business plans, market caps, and figure out what is preventing mass adoption because right now no one has heard of Bitshares.