It's not really a monetary issue. In fact, there has been a lot of discussion around here about which would provide more income: a new Freshwater program, or a free 3D background upgrade for the Marine Aquarium which paves the way for the sale of creature packs to an enormous user base. Personally, I've flip-flopped on the subject several times.
As far as a "real" programmer being able to make headway where I can't - where are they? 4 years ago I watched as some of the biggest software companies assembled large groups to come up with a competing product, only to give up and disband the teams.
For people who started with the Aquarium early on, there have been dozens of free upgrades. Clint mentions a couple, but he started with the Starfish version, which was very late in the development cycle. If you look at my statements regarding the 3D background, you will see that I never said that it WILL exist, only that I PLAN to do it, and that I don't PLAN to charge for it. Intentions are different from promises, which is why I never make promises. I've got a lot of other non-software things going on right now that need to be taken care of before I can devote my full attention to the Aquarium again (but I'm still here for you to yell at every day
).
My biggest fear is to pull a "George Lucas" - spend a quarter-century between major releases and have people be disappointed with the results.