There's often a male submissive fantasy of serving a woman that is quite cruel, inflicting many forms of suffering, humiliation, and torment upon the sub. In reality, this scenario rarely surfaces amongst Femdom couples (although it does happen, the percentage of written fantasies tends to be overshadowed by the percentage of couples actually doing this).
For this topic, I will simply try to answer the question, why is it this way?
From a submissive perspective, while they may wish for this, it's unlikely that a submissive could truly handle it on a 24-7 scale. A few hours? Sure. A weekend? Definitely. Every day for two years? Not as easy to answer. I give this one the mark of "fantasy and penis biting off more than they could chew." While it's possible in small doses, 99% of males simply aren't emotionally prepared for something like this to actually happen. Without pleasure, emotional and sexual gratification, and a worthwhile sense of self, the sub would likely either cease to exist as a person or become unhappy and rebel against his Domme.
The Domme side of things is a bit more complicated.
The first thing that comes to mind as to why there aren't a lot of Dommes out there that tend to carry this disposition full-time is that it just doesn't offer a lot to many women. I can understand why a woman would want a sex slave for pleasure, I can understand why a woman would want a sub male for domestic chores, and I can understand why a woman would want a man who is completely devoted to her and responsive to her every whim. These things provide tangible, pleasurable results, in addition to the knowledge that there is a man out there who exists merely to give her those pleasurable results.
The second thing I can think of is that there aren't many people out there with natural impulses to inflict suffering. A weekend of teasing, humiliation, and suffering requires significant planning and the ability to make on the fly adjustments as needed that remain consistent with that theme. Unless that really "does it" for her, there isn't a lot of motivation for a Domme to go to those lengths. Similarly, if/when the unexpected occurs, will she be able to react quickly and naturally in a purely cruel way? I believe it takes a certain personality type to really enjoy this and I don't think it's a very common one.
Delving into fetishes gets things a bit closer. A Domme may have a fetish for spanking or inflicting pain in a sadistic way. This I can understand a bit since it's a tangible activity yielding a specific result. On the other hand, bondage is a little bit closer. Having a sub bound and helpless does bring up feelings of power and control and it's also a matter of taking away his freedom to increase her pleasure. I believe Dommes who really enjoy strict bondage are of the right nature to be cruel.
So what about this makes things appealing to these Dommes? A few things I can come up with:
1. Knowledge that he willingly suffers for her pleasure - devotion.
2. Feelings of power and control.
3. Feeling playful and naughty.
4. It gets her off.
I have a feeling that number four is probably the great separating point between "these types" of Dommes and Dommes that don't have a lot of interest in cruelty. I could be wrong, but that's about the only explanation I could find for a Domme dressing her sub up in a maid's outfit while locked in chastity and forced to humiliate himself in front of her. Something about his suffering and discomfort has to make her tick on a deep level or she probably wouldn't do it.
I find this difference rather intriguing as certain scenarios will have one Domme hissing "YESSSSS, MOOOORE!" while the same scenario will leave many Dommes shaking their head saying "Nope, doesn't do it for me."
I know guilt probably plays a big part while a Domme is developing in terms of how cruel she can be while completely enjoying it. As long as she truly values her pleasure over his comfort that avenue can be explored thoroughly without hesitation. I believe it's probably more likely for a woman to enjoy being cruel if her early experiences with domination were with men that she didn't love nor seriously care about.