It serves the interests of existing power structures to have women feel that marriage is something of value to aim for, much easier to exploit people if they think you are doing themy a favour when in fact the reverse is true
Men need women more than the reverse
This is it, in a nutshell.
The narrative around marriage is very much that it's something women should to aspire to; they're considered a downright failure if they don't achieve it, etc. Many women then gleefully change their names to their new husband's to cement the deal, and announce their new status as 'wife'.
And then once the confetti has all been swept up, the day-to-day marriage existence is significantly more beneficial for men.
Women have traditionally played a support role in marriage - to men, their children and the very house they live in. Times change, but we know that even when both partners work full time, the bulk of the daily household minutiae (and in this, I include the thinking of everything; not just the doing) still falls to the woman.
And yes, men definitely need women more than the reverse, especially if they want children.
Then you look at other details, such as how many women forego careers - and financial independence - after marriage. Or at the very least, let their career take a back seat.
Women tend to cope much better after the death of a partner or a divorce. Many men are simply incapable of even looking after themselves, let alone a house as well.
Women will break up with men, purely because being single is preferable.
Men, on the other hand, will often get a firm grip on the next woman/relationship, orangutan-swinging-through-jungle style, before taking the risk of letting go of the previous.
Women are often also better at maintaining social ties - with friends, extended family, etc. This comes into its own when they find themselves dealing with a big life change.
Disclaimer: obviously these are all generalisations, and can't be applied across the board (my DF was widowered and well able to look after himself), but there's definitely an observational trend to all of this.
We definitely need to question this sort of thing - as many others have said, the demographic of women who are educated and independent definitely see no need to rush into marriage. Why would they? They know who it ultimately benefits.