I don't think all people are making an investment, some people are just that excited about a particular species.
At the same time, some people aren't rich, but actually give up some mighty expensive things for their hobby.
Speaking of cars....
Back in college, one of my favorite geology professors was Steven Haggarty. He is among the (if not the top) leading authorities on diamonds.
His love for diamonds (especially the rare ones) was amazing. The big grin on his face, the gleam in his eye. The guy was a riot.
Well, I always wondered why I saw him taking the bus around town and riding a bike. I mean here is a rather big name in experts, shouldn't he be making big money at the university? I asked around and according to the rumor (I never got a chance to ask him) he traded a near mint porsche for two huge Carbonados, AKA black diamonds. VERY rare, but next to useless. He got them simply because they were unique in the world...the two largest ever found. I actually held them...big rocks I tell ya.
I suppose snakes might be the same for other people. Some people just go the extremes. Its not bad.
Heck, I've always wanted an aldabra tortoise. Not to breed, not as an investment, just to have. Same goes for a black headed python, or those wicked red eyed, true white rosies I see ads for every now and then.