I had to change the hook fitting on my Hobie 17 when I ripped the "hook" off the end.
It was on of the early ones which had the flipper gizmo on it.
It was very thin, like yours, compared to the new ones.
I was told that the biggest, thickest hook fittings came on the Hobie 21 (SE, not the Sport Cruiser).
I didn't have time to order one, so I put a Hobie 18 hook fitting on.
It has bent a little, but doesn't seem to be in danger of breaking off.

I have heard of people who through bolted the fitting on the Hobie 20.
No rivets to worry about.
There is a plug below it so it can't leak.