Marriage is both a natural and spiritual institution. Though God wishes all men to be good catholics, this isn't reality, especially nowadays. Non-catholics should, and can, have happy marriages because such goals are within reach if the natural law (i.e. 10 commandments) are followed. *Some* of these pastors give really good practical advice because most problems are with human nature, which all men have the ability to understand.
So, while I agree with you that non-catholics cannot solve some problems because they don't have the proper spiritual weapons, there are still many problems they can solve, when they deal with human nature.
I find that many Trad clerics today do an excellent job teaching the theory, spirituality and theology of the Faith, but the practical side of things is often ignored. This is mostly due to our limited exposure to our priests, which mainly consists of a 30 min sermon once a week. So the priest concentrates on the 'essentials' of the faith. In times past, when rome was orthodox and we had a functioning church, there existed men like Fulton Sheen and assistant pastors of each neighborhood, who had the time and vocation to bring the faith down to the practical level and help solve problems of day to day life.
This type of guidance does not exist today on a regular basis and it is part of our suffering and persecution. God knows we need these things and in some areas, like marriage or the family, I do think *some* protestant ministers do a good job of offering 'real life' solutions and guidance, even if they are on the natural level or based in Scripture (which has a lot of practical advice, for example in the books of Proverbs, Eccelsiastes, etc). These ministers have to time to spend on research and on helping people because protestantism is a natural religion and they focus on helping humanity. But even Catholics can still take advantage of such 'natural law' wisdom and benefit from it.