It certainly contradicts the image of Christ as being the very opposite of a powerful temporal leader the Jews expected. But on the other hand, all the scripture really makes clear is that they were not royalty and not remarkably rich. The sacrifice of two doves suggest frugality and limited means, but not necessarily poverty, while the occupation of a carpenter must have been worth quite a bit in that low-tech age. I agree, it is entirely possible that the riches of Joachim are a bit fanciful.
It is commonly argued that the brothers of Jesus mentioned in Matt. 13:54-56 are actually Joseph's sons from a previous marriage
It tends to be the Orthodox preferred view, while us Catholics tend to think that they were cousins, and children of Mary Clopas.
I find it problematic that so many ideas taken AS "gospel" are based on unsupported works that the Church itself rejected as infallibly inspired.
The teaching of virginity of Mary is not based on the Protoevangelium, at least not primarily on it. The Protoevangelium is simply one coherent account that explains Luke 1:34 satisfactorily, but it is more likely that the Protoevangelium is in itself an imperfect summary of what the Church believed. As in the case of the inspired scripture, the Tradition preceded everything written. The source of all teaching, -- including all these things you hold entirely and incontrovertibly scriptural, -- is the Church herself.
How kind of the Church to assume that function of God as well. If man learns nothing from God directly, but can only learn anything through the men of the Church, then why pray to God for any sort of knowledge? If you are deciding between two jobs, your priest isn't going to instruct you on which one to take, is he? Why would you consider praying about it since God gives you zero knowledge, only the Church does? Or, do you not pray about such things?