The price is definitely too high for the BOM,
Aside from all the considerations you already made and to which I totally agree, how can you say the price is too high?
It's 170 dollars delivered. Only the LTZ1000A cost like 100 bucks. Add the pcb, resistors, opamp, assembly and shipping and for just 170 dollars I'd say it is barely profitable, assuming of course that the LTZ is new and original...
The offered part has obviously NOT a new LTZ1000A, but salvaged at best, from 1998.
New ones from digikey are still not available, stock zero, so their listed price of 102$ is obviously not a valid one.
Before the Allocation, they would cost about 50$, and about 40$ for the non-A part, for single parts orders.
Prices of that ballpark you can still find directly at AD, but for 1000EA. I think, 67$ @ 20EA order, but unclear lead time.
All my DIY PCBs with better components and very good stability, as described in the other LTZ - thread, had a BOM-cost of about 100€ each.
I also tried to reduce the cost by using expensive parts only where needed, and a single sided board.
This one has 7 of these RJ711, maybe 9$ each, where only 2 or 3 were needed, but of even better quality (1ppm/K).
So this is an additional argument, that the seller has unnecessarily used too many expensive components, because he obviously has no clue about the crucial parts of the circuit. This we have discussed up and down in this long LTZ thread as well.
Maybe that answers your question, how I can (dare to) say, that this one is too expensive.
Please also take care, that I only spoke about the BOM-cost, from a makers perspective!
Any seller can ask whatever people (who might not be makers themselves) are willing to spend, especially on a finished product.
Frank