First of all, you are unfortunately and tragically incorrect, the divorce rate among the Yeshivish has become increasingly higher in recent years. I myself know at least half a dozen couples who broke up within the year of marriage.
that might be true (i don’t know who you know or what you define as yeshivish (were not getting into it btw again)) secondly i would believe that the reason for this is based on people being more focused on themselves (either looks or not wanting to change themselves not on the shidduch process)(which is the same reason as the shiiduch crisis)100 years ago when they had shadchanim and the guy never saw the girl until right before they got engaged the divorce rate was exteremly low so there is some element of the goyishe velt in there.
did you ever listen to R. Orlofsky’s speech on platonic relationships btw?
http://www.613.org/speakers/orlofsky.html
http://www.simpletoremember.com/media/a/platonic-relationships/