Let's be real most passport Bros ain't looking for wives. They are looking for hot women to have sex with. Most dudes happily pay. That's it. They just hide the pay part cause social stigma.
The expats who are marrying foreign women tend to be older and many times choose to live in that country, which is why they say don't bring her back to America.
But even the ones that import are still doing well. 75% of marriages between Americans and foreign people who come on a k1 and k2 visa are still married after 10 years. Less than 50% percent of marriages between americans are still together after 10 years. You are still better off marrying foreign if that is your desire.