I am not joking, and I shall not tread carefully.
All the things people can describe as a reason for marriage, if you exclude sex, those reasons, things, or qualities can be found in a relationship with someone you are not married to. I could just hang out with a guy, and not be lonely, have a parnership, have love..... all those things, except sex.
Therefore we get married just to have sex, and reproduce. It cost something tangible to be married, therefore marriage is legalized prostitution.
I made a point earlier in this thread about changing marriage laws.... no one has responded to it.
If everyone was willing to enter a marriage, knowing there would be no financial benefit, I would change my mind.