Just thought I'd throw my two cents in this interesting discussion. People will always go to amazing lengths to do what makes them feel good. One of the biggest rules in marketing is find what makes people feel good and they will reward you highly for it. That's why alcohol, durgs,videogames etc are such big money. invariably they are all highs and escapes. My vice is reef keeping, and rising enrgy costs, stricter bans on collecting, (and liberal enviromentalists) have only pushed those of us who love this hobby into creating new ways to overcome the problems.
As with all markets there will be fluctuations and some people will bend with the times, but from an industry stand point, vendors and manafactureres of our products know that there is willing money to be spent in this hobby and they will find new and inventive items to keep us entertained and effeciently running for their products. A truly successful entrepenuer will see every obstacle (ie rising energy costs) as a blessed insight into what new products will be needed in the future and beat the competition to creating and marketing to an already enamored customer base.
Long story short There will always be growth in new and fascinating ways as long as there is demanders with money to spend. We exist therfore the laws of marketing say that this hobby, though experiencing a few ups and downs, will continue to grow along with our tanks.
Just me humble opinion
