These are uncapped prices? Pretty cheap compared to what I was looking at a few years ago. Back then a lot of plans had data caps, it would be like $9k for only several gigs of data all things said and done. You'd pay link speed separate from your data allotment, so a few grand for the connection speed and a few grand for a bucket of data.
They are uncapped as far as I could find, but I didn’t read the fine print or anything.
On the 4 or so companies I checked, most were metered as you said but also clearly designed for personal vessels. They were also expensive as you said; I think the cheapest I saw was ~$1500/month for 5GB, and $0.39/MB for overages.
I am in no way an expert, this is just based off like 4 links. Someone said Inmarsat had more commercial-vessel sized plans so I checked them out, and they do seem way cheaper if you’re planning to use the link a lot.
They are competing like it or not with starlink 100Mb 1TB of usage in the middle of the ocean, unlimited usage near land (within about 5-15 miles) for ~$800 a month.
In that context it's a rip off, and higher latency/lower speed.