The cost of Keiko's release shouldn't be used as a standard to measure future efforts. A rehabilitation tank, like the one in Oregon that held Keiko, is not needed, and the sea pen in Iceland was far more elaborate than needed. Of course now we're dealing with multiple orcas so there would be some infrastructure, but mostly for the human staff and logistical support, or to accommodate the public, but the whales only need a protected, clean bay or cove and an anchored net, plus a slide out, which could be a sandy beach. The overall costs might be in the tens of millions.
What would be SeaWorld's exit strategy?
How SeaWorld might be induced to set the orcas on their path to freedom could be quite variable, resulting from financial and/or legal necessities. If California's AB2140 passes in 2015, the ten orcas at SeaWorld San Diego, one of the pseudo-pods, would need to start this process. Under this bill, SeaWorld must fund the rehabilitation. Once the law is passed, SeaWorld would be forbidden to export the orcas. If passage seems likely, however, mightn't SeaWorld begin transferring the orcas to Orlando, San Antonio, and foreign marine parks? While capture and importation of orcas are highly regulated, export is a minor formality.