Of course, that's speculation just like what you posted. And personally, speculation isn't squat when it comes to Scriptures. Isn't it those who don't agree with the Catholic Church that are always talking about never adding to Scriptures? Then why should your speculations be any different?
No offense, but they're not, your speculations are simply "comfort food" for your preconceptions and nothing more. I have a lot more reason to believe what has been handed down as oral tradition for over two thousand years from those who personally knew both Christ and Mary than I have to believe anything those who decided to leave the Church Christ founded several hundred years ago have to say.
Regards
Perhaps so, but your speculations are an integral part of your doctrine. You REQUIRE your speculations to be so or your theology crumbles. If Mary had other children your Maryology goes up in smoke. If Mary didn't have other children, my theology changes naught.