Hey everyone. So, we know that the Habsburgs were famously adept at strategic marriages, and this had the consequence of different brances of the House of Habsburg frequently intermarrying to retain power. As time went on, the gene pool got more limited, until eventually the very strategy that they used to hold power rendered Charles II of Spain unable to produce an heir. The War of the Spanish Succession happened, the Bourbons got Spain, and this practice became a lot less relevant until eventually the Austrian Habsburg Marie Antoinette would marry the French Bourbon Louis XVI.
Is there a way that the Habsburgs could have pursued a more sustainable marriage-succession policy? Maybe an earlier Pragmatic Sanction? When would a Pragmatic Sanction have been most viable -- perhaps after an alternate Thirty Years' War, which ends in Catholic League victory (or Protestant League secession from the HRE), and the House of Habsburg is secured as a hereditary Imperial dynasty?