Assuming events delayed or blocked Spain from getting easy access to the Pacific as it did IOTL-for example, Magellan lands on the wrong island in Polynesia and gets killed and eaten, or as a butterfly of the common "The Aztecs/Incas kill the conquistadors" scenario, how much longer would the Spanish-either the Crown or private expeditions-continue to try to sail to the Indies while respecting the Treaty of Tordesillas?
While Magellan reached the Philippines in 1521, it was not until 40 years later that the Spanish started to colonize it, which does indicate that Spanish interest in reaching East Asia spanned across decades. But could that interest survive failed conquistas and the loss of the pivotal expeditions of OTL? Would Spain keep throwing ships across the ocean until one stuck, or at some point would they cut their losses to keep focus on the Mediterranean and New World?