The problem with actualizing your fantasy encounter with a MILF is in the 'M' part of the acronym - 'Mother' - ergo, a single mommie with all of the very "real world" baggage that goes along with that. I've tapped my share of older women when I was in my 20s and I can tell you that the sex was no more or less extrordinary than the younger women I've been with. The only major difference? I never had to worry about 22 y.o. single girls finding a babysitter for a night or had to be concerned with her making too much noise during sex so as not to wake up her son in the next room. Nor was I concerned about it being "her weekend" to have the kids.
It's very easy to assume single mothers are victims by default - some are, most aren't. Trust me, a majority of single mothers are single for a reason - and it's not always because of their Jerk BFs or deadbeat husbands. The common belief is that MILFs encourage an idea that they are more sexually available; you've got to ask yourself, why would they be motivted to be more sexual while single than when they we're married or in an LTR? They become motivated to be sexual and hit the gym when single, but wouldn't make the same effort when married, why? Because the guy wasn't worth it OR because she became comfortable, he lost interest, became fed up, and she's prompted to be more concerned with all that in order to achieve a long term security with another man that necessitates she do so?
Don't get me wrong, there are attractive women in their 30s & 40s but these are uncommon exceptions to the rule. The social reinforcement of the MILF fantasy is just a modern extension and evolution of the "she's still got it" social convention with the latent purpose of leveling the playing field for 30-40 something single mothers unable to sexually compete for the same calibre men with 18-28 y.o. women. The harsh truth is that a beautiful, sexually available, single woman in her mid 20's is at a decided advantage for sexual selection than a single mother entering her 30's who's encumbered with all the responsibilities of being a parent.
Schedules of Mating issues aside, even when both women are equally attractive and equally sexually available, the childless woman is still at an advantage because she comes with less liabilities and represents a "fresh start" in comparison.
Women's sexual value naturally declines as they ages - it serves an older woman's purpose if she can redefine sexuality as her conditions change through life, and convince herself and society that she's correct and genuine. Ashton Kutcher and Demi Moore may epitomize this fantasy, but in reality, there are thousands of women filling gyms across the country for every Demi Moore convinced that they "still got it" while every year a new crop of 22-24 y.o. hotties commands the attention of the same men they're competing for. This is just the natural extension of the 'Have It All" lie that women have been sold for the last 50 years. Men only too eagerly buy this convention as well because it facilitates a Buffer for them and (presumedly) presents an easier route to getting laid. Therefore it is also in their interest that the myth and the Buffer be reinforced.