Why do they do it?

You have probably been the victim of a 'scam' artist at least once in your life.
I seem to be finding that there are more and more of them sprouting from the detritus that litters humanity, with Nigeria seeming to be the central point of highest contamination (followed closely, I fear, by the Costa del Sol where I have made my home).
Scammers seem to be able to devote time and effort to producing something that has appeal to some people and these people appear to be ready and able to part with large sums of money.
Why, I wonder, don't scammers put their obvious talents to more regular use?
Why do scammers scam?
The obvious answer is, because they can.
They make enough money by being able to fabricate a reality that pulls in the unwary to not have to worry about any questions of morality. In a fabricated reality, they can tell any sort of lie they want to in able to satisfy their victim that everything is above board and proper. Since the victim will probably be a 'hit and run', the scammer doesn't even have to remember what lies he/she has told.
Once a scam has been in operation for a short while and the victims fleeced, it moves on and either becomes something else (though still a scam) or simply relocates.
Why do scammers scam?
Another answer is that scamming is ridiculously profitable.
I don't know why it is, but the most successful scams seem to rely upon the victim being aware that what is being asked of him/her is slightly illegal but the only losers will be 'nobody'. They seem to want to be able to remove $10.000.000 from an account which a countryman of theirs put into a secure depository just before being assasinated, being killed in an accident or dying from some other unforseen circumstance. (This is just one of many scenarios.) It is not quite legal but there seems to be no victim. Maybe it is the thrill of the idea getting away with something.
Scammers scam because they can make a lot of money and because there are a lot of volunteers out there just waiting to be fleeced.