I've worked as a psychologist and my primary focus was family therapy so I speak from a professional point of view. There are a number of factors to look into here.
First, the quality of marriage universally depends on personality compatibilities rather than anything else. Physical features change, financial situations change and much else but if one finds the other's company rejuvenating then the relationship is likely to last long and be fulfilling.
Secondly, marriage success has to be defined, speaking within Pakistan most marriages last long but the marital satisfaction can be abysmal. So it depends on what we mean by success, quality of the relationship or the quantity of duration? You'd often find our people lamenting on divorce rates which is increasing globally but forget to look into the data showing high levels of remarriage as well. Again, what do we mean by success.
Thirdly, there was a research done in Pakistan by the Quaid e Azam university and it showed what affects marriage regardless of the type: it's the family involvement levels, if it's high i.e. the families are highly influential in the relationship and there are problems i.e. friction then that's the highest rate of marital dissatisfaction and dissolution. Couples having problems within their own relationship are surprisingly fewer than having problems stemming from the larger family sets and this is where one has to be able to set boundaries, compromise and navigate. I would say that it's this point that deserves the most focus from a prospective couple along with their own compatibility