Historically, latex has always been a labor-intensive enterprise, from sourcing, shipping, to manufacturing. That's only gotten more complicated with ongoing supply chain issues and tariffs.
Rubber trees only grow in more tropical environments, like Southeast Asia, South America, and some parts of Africa. Getting rubber tree sap in its raw form takes a lot of manual labor, as extracting it from the trees has to be done by hand and very carefully. This process, called tapping, takes time to execute correctly. Once that's complete, it's not a matter of letting the sap just pour out—it has to drip into a bucket over several hours before being collected, tree by tree. All that is before the raw material is packaged up, and undergoes shipping abroad, eventually being turned into latex via the vulcanization process. This is essentially baking the sap at high temperatures so that it solidifies, flash freezing it (different temperatures dictate if it will end up being Talalay or Dunlop), and finally, it becomes latex as we feel it in our mattress.