How about a flying drone that drops an inflatable from a few meters above the struggling swimmer?
And you can buy them off the shelf, hell you can buy a drone right now today that can physically lift the person out of the ocean.
From TFA, the cost for the boat was around $12k. That means this is about 4x more expensive, not 20x. That doesn't include the droppable inflatable boat but that is probably not going to break the bank either.
1: https://www.insidehook.com/culture/little-ripper-rescue-dron...