<<<”Every single person I know who left the Roman Catholic Church did so for theological reasons,...”>>>
You are correct. They could not follow the Magestirum of the Church. They needed contraception and most importantly, the divorce and remarriage direction was to tough too follow. They would rather “think” for themselves rather than obey. It is why they search for years finding those Churches that are “permissive” or at the very least undefined in their actual teachings. The easy way out should I say? Easy way out for those who have no discipline or have never been directed in discipline.
In my 20+ years in the Evangelical world, I have found that the percentage of ex-Catholics who went Protestant for the above reasons, is exceedingly small.
If anything it's the opposite: they're attracted to Evangelical Protestantism because that's whose actually teaching the Bible and biblical living. The Catholic church, by contrast, has really dropped the ball on Scripture teaching, despite St. Jerome's admonition ("Ignorance of scripture is ignorance of Christ").
As for contraception, (a) it isn't clear from the scriptures alone, but nevertheless (b) I do seem to encounter more non-contracepting, large, natural families in the Evangelical world than I do among Catholics... why is that?