Low supply due to low demand? Yes. Niche market items are always hard to find because there is such a such a small market to begin with.

Low cost due to low demand? Generally, no. Only when attempting to clear out stock. The economics of scale pretty much dictate that niche market items are going to cost more than mass market items.

As an example, the current hardback edition of Mirriam-Webster's "Collegiate Dictionary" has 1667 pages and retails for less then $30. Most households have at least one copy of a dictionary.

Comparatively, the current hardback edition of Kreyzig's "Advanced Engineering Mathematics" has 1280 pages and costs $197. Most households do not have a book on post-calculus mathematics.

So, needless to say, Mirriam-Webster's has a much larger demand. Subsequently, a much larger supply, and lower prices due to the economics of scale.

Politics really doesn't figure into it with the exception of heavily regulated items (i.e. guns) and items purchased on futures (gasoline). With those, politics can really throw a market up or down.