No offense intended but you sound as if you were a scammer yourself
And now you are sharing the secrets of the trade with us. Though I disagree that scammers are always keeping the deal moving, no matter what. Once I read some pretty scientific investigation into the matter (namely, into the so-called Nigerian Prince emails aimed at extorting money), and the conclusion was that the scammers drop communication instantly as soon as it becomes evident to them that their target won't bite since continuing would be a waste of time and effort for them
Deisik, you're referring to the "419 scams" that were famous for originating in Nigeria - I think I also read the same research into it. Scammers are a lot more complex in operating than we give them credit for. The 419 scammers aren't much different from the ones here. Wittingly or not, they actually know the type of people most likely to get conned, and will only move the deal for as long as the targets fit the profile. As soon as it doesn't, they drop the target.
The mistake we make is our underestimation of scammers. We liken them to be immature, below average in intelligence and uneducated. While it is true that a lot of their methods are unsophisticated and their language awkward, this in fact can be deliberate and helps ensure the right targets are attracted. And scammers who recognise our underestimation then give us what we want: maturity, intelligence and educated manners.