>which provide high paying jobs to American sailors.

I don't think this is the original purpose of the Jones act.

It was #1 to keep a shipbuilding industry alive in the US. It was added just after WW1 to avoid the current hand-wringing about allowing advanced chip manufacturing to mostly move offshore.

The #2 reason was similar - to keep a ready supply of merchant marines (civilian sailors) available if needed for another major war (note, that is a different reason than "create high paying jobs", even if the two overlap).

The #3 reason is because foreign-flagged ships have almost zero safety checks (today probably 95%+ are flagged in Panama or Liberia because they are cheap to register there and have no real safety standards or inspections).