What the question really boils down to is this: Are people happier in general in societies with predominantly arranged marriages or in societies with love marriages. It would be great if we had this dataset directly, but without the data, we can say that about 1/2 of every marriage in non-arranged cultures end up so unhappy that they break up. We do not have corresponding data for societies with arranged marriages if what you say is taken into account.
But in general, if so many of these non-arranged marriages are dissolving, it seems to show to me that simply letting the young people choose without any vetting process is not leading to good results. A 50% failure rate is not acceptable.
Your argumentation bypasses the fundamental issue.