Manly will be okay in the short term, but if I were a Manly fan, I would be suspecious of the property developers ofloading Manly to the Sunshine Coast.
I can see them getting a deal with the QLD Gov to build a Leagues club and upgrade the stadium at Kawana Waters for very cheap, then developing/selling off Manly's Sydney assets at a huge profit, pocketing the profit and leaving the club.
I really think that this is what Delmage's plan is, and unless there is some uproar at the club, they will keep inching towards that end. Especially if the North Sydney/Central Coast Bears come back, as that makes Manly even more fringe.
Clubs with niche markets and low apeal to people outside their area will have some big problems in future (examples being Manly and Cronulla). The writing has been on the wall since Wests shifted to Campbelltown and Newtown got the boot, expansion outside Sydney, Superleague, Criteria, Mergers. They have managed in their own ways to continue, but the nature of club sport these days will catch up with them.