How does unit economics work on this kind of items?

I was looking at some items in Kitchen category and I am failing to understand how the unit economics would work.

For example, take asin B0D4JBDPP8 It is retailing at 72$ Item weights 10 lbs so heavy to ship.

Looking at costs:

Amazon’s commission : 10.80 FBA 3PL approx : 12.00 PPC (30% AcOS) : 21.60 Inbound shipping : 2.00 Misc (returns etc.) 10% : 7.20 CoGS, ocean freight , AWD etc. : 15.00

So that is around 3.40 gross profit per unit.

That amounts to about 5% gross profit. If you include the administration, customer service and other business costs, that is almost zero. If any of the costs go up due to unforeseen reason, you can easily make a heavy loss. I have not even included labor.

How does this make sense? Are all sellers operating on such razor thin margins?