Like anything else, quantity will eventually affect price, and/or competition will force the issue.
It is a safety item, and if this truly solves the problem, it would be hard to argue that the price is too high.
Ease of hookup (and conversely, ease of unplanned swimming) would be a valid concern, but other than hearsay, are these real issues with these designs? Are there conditions that are more likely to separate the ball from the socket (rough water, etc.)?
Again, the ball system from the 80s/90s seems to have worked just fine.
Mike