What becomes of the Inca if Spain does not colonize western South America.
Inca or successor Andean native states evolving and surviving until 19th century colonialism
Likewise, what happens to the pueblo indians long term and the other lands of northwestern and greater mexico without spanish colonies.
The Pueblo and other Amerindians from northern Mexico to California to Texas are in self-governing groups, probably getting sheep, goats and horses later, not yolked to Spanish missions and deal more with whites for fur trading later.
Long, long term, Anglo colonization is probable eventually. Cannot rule out a French, Dutch or Russian presence though.
Finally what impact is this likely to have outside of the new world.
Less silver for the Spanish government, with short term bad effects and maybe longer term good effects. Hungary and Bohemia may do better in an altered silver market. Of course Andean precious metals will still be acquired, but the Spanish and others will need to provide articles of interest to trade with the Andeans.
If successful in holding more of the Caribbean, Spain gets more sugar revenue, but they may never produce as efficiently as the Dutch, British or French plantation systems. Spanish crafts and manufactures could benefit from supporting Spanish plantations and making goods for the Andean market.
I think there are going to be limits to how much of the Caribbean Spain can hold however. A focused defense could theoretically help preserve Spanish rule in Jamaica and even more so in Hispaniola, denying the French a spot there. However, I think that holding every little last bit of the Antilles, especially the Lesser ones, is not too likely - the value of defending and holding each and every small island, especially in the eastern Caribbean/Lesser Antilles for Spain, is less than the value to England, France or the Netherlands or Denmark of getting a couple plantation-able Caribbean islands of their own. The Lesser Antilles, and even Trinidad, are more exposed to the Atlantic.
Spanish efforts focused on the Caribbean, unless they are a total fail, should preempt at least the British enterprises in Belize and the Miskito coast in Central America.
Florida meets the definition of "near the Caribbean". Maybe if not attempting to go to northern Mexico, the Spanish will do more with St. Augustine and Pensacola in Florida.