Certainly a lack of formation in a family, and small families, contribute negatively towards vocations. The sentence of mine you quoted was a response to @jack63’s post, which (if I understood it correctly) seemed to imply a general level of education among the population of a diocese plays a significant role. If he was not referring to education in the Catholic faith specifically, and his post certainly implied that is the case, then I disagree with him strongly.
Indeed, a large part of vocational crisis is exactly what you say. A lack of vocations is an effect of a weak Catholic faith in a time or place. We watered down faith formation in the 70s, we abandoned the rosary, we abandoned Eucharistic adoration, we actively discouraged frequent confession, we allowed liturgical abuse to run wild, and guess what: vocations dropped like a rock. Its a hard cycle to break. But it has to start with the basics. Get people back to doing the basics and some of them will learn their faith, and some of their kids will become priests.