The post Why are Thunderbolt 2 adapters so expensive was closed as not well-suited for this site because it is about hardware shopping and focused on price.
It is true that when the primary focus is about price, answers get out of date quickly, and a site like this is not well-suited to answer "what is the best external hard drive for less than $100" – such answers become obsolete almost instantly. This site does not do well answering questions that focus on the market price of things.
Questions about "what makes items in category X generally cost more than items in category Y" seem to be a fundamentally different thing. It's not asking about "Where can I find a cheap Thunderbolt 2 adapter," but asking what issues tend to contribute to higher prices for Thunderbolt 2 peripherals compared to Thunderbolt 3.
While it might be difficult to make this a directly actionable practical question, the answers are likely to lead to a deeper understanding of technologies and help people make long term decisions related to their adoption.
I therefore propose that while questions related to hardware shopping that focus on market price, which fluctuates rapidly, be closed as off-topic, but questions that focus on the factors related to the fundamental costs of an Apple-related technology (to be sure, one of the factors related to price, but far more persistent and likely to produce an answer of enduring quality that may be useful for years to come) be considered on-topic on this site.