They've been commercialized for some time.
Quick DDG search for "portable desalinator" finds many hits, like http://watertreatmentcorp.com/1-6-emergency-portable-desalin... with:
> The JHH-SWBX series portable desalination watermakers are designed to convert salt, brackish or unknown water sources into pure drinking water within seconds and with just a push of a button. This makes it ideal for applications that require an easy to use watermaker, such as field operations, fishing vessels, salvages and more. Our products feature an ideal size, making them portable and ready to use anywhere. These watermakers operate using AC or DC power according to customer requirements.
The abstract for paper at https://pubs.acs.org/doi/abs/10.1021/acs.est.1c08466 . even comments "many reverse osmosis-based portable desalination systems are already available commercially".
