After much investigation today, I learned;
The Jones Act does not prevent ships from foreign countries to enter Puerto Rico. It prevents foreign ships from taking supplies from American Ports to Puerto Rico. If Mexico sent a ship to Puerto Rico, it could do so.
Where people are saying the Jones Act is "strangling" Puerto Rico is that there are ships delivering goods in American ports right now that want to haul supplies to Puerto Rico and they cannot because they are a foreign ship and cannot ship from one American port to another. An American ship has to do that.
They say there are a ton of supplies sitting in San Juan right now, but that there is a large shortage of truck drivers to distribute the goods. The Jones Act doesn't affect truck drivers in Puerto Rico.
As soon as the governor of Puerto Rico asked for the Jones Act to be suspended, Trump did it. Before that, many people told Trump that Puerto Rico was getting plenty of supplies but where the problem lay was in distribution.
Regarding the Jones Act for Florida and Texas, hell if I know other than a couple of news articles that I read said that the push for that suspension came from politicians in those states, but that Puerto Rico has little representation in our government.
Blame politics. All parties are guilty of it.