Well I would say the majority of detectorists dont make much of a profit, if any. But most of us dont really intend to.
That being said, were not in it to get rich. Its just nice to get out and dig, and find interesting items and explore historical areas, and learn things.
Now, with the price of a decent metal detector and the time devoted to your hunts, it can be quite hard to justify that your going to make back your investment.
As long as you can come into the metal detecting world with the mindset that its a hobby and not a career you will prosper. But hey, your bound to come across great items sooner or later, and heck if you find something really valuable thats just an extra plus. Youll end up popping something awesome from the ground when you least expect it.
Also, You also mentioned the recession, Im not sure if people will pick up the hobby for financial reasons or not. What I do know is, this recession economy has driven people to take desperate measures. Apparently many people are once again packing up and heading out west to dig for gold, its starting to spark another full blown gold rush.
-Kyle