MSS: this topic is really too hot for me to tackle but I still feel the need to add my two cents. It’s nice to hear about the sincere singles and couples you are dealing with — however in all fairness is it not likely that those abandoning yiddishkeit aren’t sending you their shidduch profiles?
Also, all of us should remember that a Yid can not remain stagnant, we either grow spiritually or fall. If someone is holding on to only a few mitzvos to start with, when he (or she) falls it is only these few precious mitzvos that are “available” to be dropped.
At the other end of the spectrum are the sincere MOs a few posters mentioned whose idealism allows them to take great strides. They have a good, knowledgeable starting point with lots of room for growth, which in turn spurs them further. Counter that with “frum” ffbs which when they become lax in their observance [most] drop minor stuff first, and either continue to drop or hopefully mature spiritually and pick themselves up without major harm having been done. OTHD too many are disillusioned and don’t have the drive to grow as their yiddishkeit was handed to them on a silver platter. (the yiddish monthly ma’alos had a good article on this last point a few months ago.)
Those that do strive for more hopefully won’t be ridiculed here and elsewhere as being fanatic — tolerance should go both ways.
Last point, I don’t recall who mentioned it but it’s not exactly true that “especially chasidic” disown their OTD kids.