Whilst cohabiting and single parents may have lost the whole taboo factors, the idea of marriage too has changed and this is not ONLY due to the mentioned reasons.
Many of my friends today are choosing to remain single and/or postponing marriage for many reasons. Even the religious ones who would never have sexual relationships out of wedlock.
One of the biggest reasons being that women today are far more educated and independent and hence don't wish to marry a man purely for the sake of finding a provider and/or to please parents,relatives etc.
They prefer to think over each prospective groom more carefully,do a lot of research and make sure they are making the right decision before taking the plunge. And they can afford to do so,literally, as most of them are earning their own living and having quite good lives.What they look for in a spouse besides to fulfill their carnal needs, are men who will compliment their lives, and make good companions and of course be exemplary fathers to their future children. And to find such men may take time but will be worth it, since the chances then of incompatibility and finding the man you wed is some kind of monster is reduced by far.
In the recent years, having seen the divorces of many people, including my own parents, I can truly say that a majority of these cases occurred due to the couples in question marrying in haste and/or for wrong reasons.