Years ago the Reform movement came up with a great advertising idea: it's hard to be Reform. According to this concept, it's easy to be Orthodox - you just follow all the rules. It's also easy to be Conservative because there were still lots of rules. But with Reform, it was really quite difficult to be a dedicated Jew because there were no rules. One pretty much had to make up one's own and stick by them which is a lot more difficult that following a guide.
A few years later, the Conservatives released their own version. The Orthodox position was the same - just follow the rules. Being Reform was also easy because you just made everything up as you went along. Ah, but to be Conservative was difficult because you had to find the right balance of tradition and innovation. That was hard.
Orthodoxy never came out with its own view on this subject for a couple of reasons. For one, there is no central authority in the Torah-observant community like there is in Reform and Conservatism. For another, we know that the hardest way to be is observant. Yes, we just follow all the rules but have you ever looked into how many there are of them?!
Flash forward a couple of decades and the results of these views is now apparent. Of the three dominant so-called streams of North American Judaism, it is the Conservatives that are in the most trouble.
In truth, it's quite easy to be a Reformer. Heck, you don't even have to be Jewish to belong which is how the movement props up its numbers. Easy conversions, patrilieal descent, prayers only twice a year and near-complete flexibility in belief and practice sustain the Reformers even as assimilation chips away at their existence.
Orthodoxy is also doing quite well despite the lack of success every other Jewish group wishes it. Despite a steady stream of folks leaving, more are being born or joining voluntarily into it. And as non-religious participation in Jewish community life decreases, Orthodox influence grows.
But the Conservatives? They have a problem. It was one thing in the post-war years when society was repulsed by the nationalist and extremist feelings that had powered fascism only a few years before. Conservatism was the perfect movement for the time since it eschewed both near-complete assimilation as well as complete religious dedication. One could be a good ritual Jew but live a thoroughly North American life as well.
Society has changed since then. Extremism is, for better or worse, back in fashion. You either stand for something or you stand for nothing and few want the anonymity a lack of firm beliefs in something provides. This has created a flight to the edges with people either completely dropping out from Jewish life or becoming baalei teshuvah and embracing the observant lifestyle. The compromise that Conservatism used to represent isn't in fashion so much anymore.
The other problem is how Conservatism has reacted to this change. Instead of firming up an identity of its own, the movement seems to have determined that the best way to maintain its numbers is to move to the left, to out-Reform the Reform if possible. This has led to multiple initiatives over the last few decades like women rabbis, egalitarian services and homosexual marriage. Yes, the veneer of the approval of the Rabbinical Assembly and its so-called halachic process is still there but the process itself is a farce as vote after vote leads to an endorsement of positions the Reformers have held for a long time.
The membership isn't fooled either. Why hang around in a pseudo-Reform movement when the real thing is next door? Why pretend to be ritually observant when the Temple down the street dispenses with much of that archaic formality but tells you you're still a good Jew?
Yes, there are those who will deny the problems, as this article from JTA demonstrates. One can always point to buildings opening up and new initiatives as signs of success. However, the facts on the ground as far back as 2003 and more recently show a different picture. People are leaving. The uncommitted are either moving left or dropping out. Those with a serious interest in Torah and Judaism are moving into Orthodoxy. There is little interest left in a movement which promises mediocrity of both extremes when folks are only interested in excellence in one.
Will Conservatism disappear in the short term? Of course not. There are still too many institutions, too many folks with too much invested for anyone to talk about rolling up the carpet but within a century or two it is likely folks will talk about the Conservatives the way we talk about the Karaites - a blip in history that folks thought was a good idea at the time.