I would not consider the Texan movements for secession to be comparable to that of Puerto Rico. Puerto Rico is not a state and exists in a quasi-colonial relationship with the United States and has essentially no material vote in the national Congress. The rights given to California and Texas as states in the Constitution are not available to Puerto Rico. This is a fundamentally different relationship to the federal government of the U.S which, consequently, makes comparing Texan secession and Puerto Rican independence a category mistake. Being essentially different types of political entities means that declaring "independence" mean two very different things.
One important consequence of this manifests itself in PR's ongoing massive debt crisis. The U.S does not assume the debt of the Puerto Rico like it might the debt of any state. Further, PR's commonwealth status basically made it a tax shelter for a really long time (PR can issue debt tax free, so investors want to own that debt for obvious reasons). That means that most of Puerto Rico debt is held privately not publicly. Therefore, while PR obviously has to come out of this debt crisis somehow, there is no national public stake in their debt -- hence, the U.S federal government essentially not giving a crap about how much money PR does or does not owe. Unlike a state, PR is not protected by U.S. bankruptcy provisions.
The other problem is "national identity". In another post you readily admit that any Texan considers themselves an American and that state pride and national pride go hand-in-hand. After 12 years in Texas, I would agree with this assessment. However, Puerto Ricans have a separate national identity from the United States. They are "Americans" and "U.S citizens" yes, but in addition to that they are also "Puerto Ricans" in a much richer sense than a Floridian is a Floridian or even a Texan is a Texan. To use three trivial examples of how this national identity is separate from that of the rest of the U.S, Puerto Ricans speak Spanish primarily, exist in a modern colonial society as opposed to a fully autonomous member of a federalized republic, and are largely Roman Catholic instead of Protestant. None of this makes PR a separate country, to be sure, since that is a political definition but all of these factors and more make it so that one could argue that PR is its own nation with an identity more closely resembling that of the rest of the Caribbean than of the mainland U.S.
