Popes don't have the power to make falsehood into truth. Such a "ruling" would simply be null and void.
The reality, as I'm sure you know, is that the Pope is the only major figure in the world today standing up for the historic Christian position that the procreative aspect of sex cannot be discarded, not even within marriage.
That was the unanimous position of Christendom prior to 1930. Now every major Protestant group, and most of the Orthodox, can find nothing wrong with birth control. But, in an unusually prescient moment, the former Archbishop of Canterbury said flatly a couple of years ago that, by permitting contraception, the Anglicans had said sex for pleasure was its own justification, and that, having made that admission, there could be no real argument for opposing homosexual practice.
So, I'll bounce the question back to you: what if, instead of caving into the culture beginning with the Anglicans in 1930, every Christian denomination had maintained the position held by the Reformers, that contraception was a sin? Do you really think that we'd be worse off?
As the apostolic successor in New Hampshire has already done?
He may think he's an "apostolic successor," but Roman Catholics don't recognize his ordination, or that of any other Anglican cleric. He's a layman wearing clerical dress, as far as we are concerned.