I have an odd feeling this is beginning to get a might bit aggressive, who would have thought?
It's great that you purchased that large of a tank and had that large of a tank available right away. If I could disagree with you on a couple of points, and agree on others:
Pet licensure is a fantastic idea. As I have it some parts of Europe require it. They also require spaying/neutering without a breeders license. Really cuts down on the unwanted animals and ignorant animal owners that we see here in the states. The difference is of course, my shark isn't going to form a roving pack if I let it go.
On tank size, bigger is great but not always better. The analogies have hit a little of key though. I keep my juvenile monsters in a small tank for safety and convenience. If I have a two inch pbass, I'm going to keep it in a 30-50gallon tank until 4-6 inches. This way I can find it to measure growth and health easily, and I don't have to worry about future tankmates eating the damn thing. Don't get me wrong, I love getting small monsters and watching them grow. To continue the analogy, it's not a difference of bed size. Comparativley letting your baby roam around the house whilst you watch through the windows is a better example. Then again, the other babies in the house aren't in a great deal of risk of being consumed either are they?
We all do what we can and we come here to share insights and ideas. As a result we tend to weed out the casual keeper. No reason to be discourteous billbob, you are not preaching to the choir, you are coming down on your peers for exactly the point you are trying to make.
On the topic of monster fish keeping, please don't patronize. The biggest tank I've seen on here is a 52,000gallon. It's infamous of course but I wouldn't expect arapaima to tell us it's the recreation of habitat. There simply is no way for us to recreate the amazon in water movement or turnover. Especially so for sharks and rays. A 10,000 gallon tank is by no means close to what a shark can swim in moments in the sea. A 1,000 gallon tank is nowhere close to what a pbass would swim in the wild. For all of the fishkeeping we do, we are still doing our best, and that's all we can do.
I have delusions that I find humility in sharing the bad decisions I've made in the hopes that I will grow as a person and another may heed the advice. While I do understand the condescension you feel, there's no reason not to be civil.
Swim on!