Why is it that most adult webmasters continually try to increase their traffic levels, even if they arent making any new sales?

Im always seeing threads on a variety of forums saying that people are working on building up their traffic levels, yet with this incrrease of traffic, no increase in sales come.

Surely it would make more sense for these people to maintain high levels of profit than to raise their expenses and decrease the amount of profit that they are making from their sites?

Dont these webmasters realize that the more traffic they get, without making more sales, means they actually make less money in the long-term?

Regards,

Lee