familygirl – Moden day Shidduchim can be a nisayon – The crisis is not only because everyone is so picky. You cannot choose to which family you were born into. If your family have disadvantages that others reject them for shidduchim, then that is not the fault of the particular boy or girl in the shidduch.
Money is a particular problem. If you are born into a poor family, or a family whose parents do not have a regular job, you are going to be rejected or at least looked down in the shidduch market place.
Likewise if you are not particularly good to look at, or physically not beautiful, there is not much you can do about that.
I would say both of these things and other factors as well are a nisayon from Hashem.
Likewise of you were born into a non frum family, and are a baal(as) teshuvah, you may be rejected from shidduchim. This is another type of nisayon.
Just like Dovid Hamelech was ruled before he was King, that he could not marry an Israelite girl because he was a male Moab descendant, that was his particular nisayon. The rejection led him to pour out his heart to Hashem in prayer as the Psalms. When Hashem heard his prayers, not only was the decision reversed but he became King of Israel!