Don't worry, men are starting to be treated this way too!  Soon we can all be neurotically preoccupied with our body images together!

It's an interesting question, Alice, and I agree with you that although certain basic problems (both those of sexism, and also racism) have been addressed, other basic ones remain entirely untouched and the efforts at reform seem to have run out of steam. In the US for instance, despite electing a black president we have largely failed to deal with the social issues (poverty, incarceration, and many things which I'll just call "not belonging to the elite" -- mediocre education, uninteresting job possibilities, etc) which race correlates with for many people. Likewise, it is important not to discount the basic ways in which women's lives and opportunities have changed in the US in the past 50 years -- we can now buy houses, open bank accounts, obtain contraception (mostly), and at least in principle, apply for most jobs and for some part of every day, live under the illusion that gender does not matter.

At the same time, there's an enormous and subtle weight which rushes up and undermines these gains on a social level. The gates to the prison were open, but now the dream factories tell us we don't want to leave, and many people believe it. As a silly example, I was idling around on youtube the other day, and ran across some women's fitness and bodybuilding videos from the early 80s. We're not in that era anymore! That exhilarating sense of power and self-determination seems to have collectively fizzled. Walking down the street one can't help but be astonished at the incredible sexualization of very young girls, as well as the feminization of adult women: it's all kitten heels, skirts and ruffles in the department stores now, and last season it was all about fifties fashion. And I'm not saying this is just something men do to women: it's psychologically complex, and we're all involved in it, and it would behoove us to understand how.

I'm inclined to think that Mia's great post about psychoanalysis is relevant here: when you try to get an entire society to change by bulldozing the tip of the iceberg (that is to say, what you can see), sometimes the ultimate effect is that you now no longer have any leverage on the diffuse, invisible, enormous subconscious resistance...

I'd say there are multiple reasons that feminism lost steam and that sexism has become increasingly acceptable.
1. The women's movement of the 60s and 70s did a great deal of good--passing essential legislation, championing court cases, inspiring women to run for public office and other positions of power, and raising public awareness of discrimination. Ultimately the movement focused its attention on the ERA. This was an exhausting effort, trying to get the necessary states to ratify the amendment, and then it failed. By that time, most of us were tired of the work we'd been doing (unpaid, of course) for women's rights and drifted off to careers. Many, like me, got divorced and went to law school or some other profession.

2. Meanwhile the right wing took on a very effective campaign of demonizing feminism. Femi-nazis and so forth. They convinced the generation growing up in the 80s and since that feminists were neurotic man-haters, very unpleasant and unreasonable people. Girls did not want to identify with such a denigrated group and became afraid to mention sexist behavior for fear of defining themselves as feminazis and bra-burners--crazy, ugly women.

3. Laws against sexism have been very poorly enforced, putting those women who have the courage to complain in a vulnerable position. Men still hold the power in virtually every industry and institution, and they sweep sex discrimination under the rug, along with firing the woman who complains.

4. The media, still owned and run by men, promulgates images of women that satisfy their own fantasies. The emphasis is on sexiness and pleasing men. 

5. Our educational system still glorifies men's wars and says little about the accomplishments of women. I'm tutoring a 16-year-old in US history, and last week he was assigned the task of memorizing the dates of every war in which this country has been involved. But nothing about the essential role of women in raising and protecting families, founding schools, charities, and hospitals, nurturing cultural events, and building communities. All of this has been primarily the work of women--holding together a civilization that men seem intent on destroying through wars and other forms of violence. 
I spoke to a local high school junior English class recently about the women's movement of the 70s (Bless the teacher for inviting me!) and discovered that not a single student had ever heard of Roe v. Wade. I was dumbfounded. They know the dates of every war but nothing about the most important SC decision of the last century--a decision that did more to change our cultural mores that any other single event. Just another instance of relegating "women's issues" to the margins.
My friends in academia tell me also that women's studies' courses are increasingly taught by women who are not sympathetic to women's rights. Very clever strategy by the right wing, I must say.