It's not necessarily that they don't want to teach; it's that teaching's not rewarded. This is particularly true at Tier 1 Research institutions. You're teaching evaluations play very little role into whether or not you actually get tenure. You have to work on publishing and grants.
I'm not sure (b) there is correct. I believe if the copy itself is not for sale in the US, the library could be in trouble. It's not the purchasing that's an issue, it's the lending, since the reason libraries can lend books is Section 109.
Furthermore, I'm pretty sure that most large libraries have imported books in their collections- books in other languages, or certain collections that are made primarily of books from other countries (for example, research libraries or collections on a specific geographical area). If I recall correctly from some of ARL's earlier works when examining the Google Books issue, at least 20% of most research libraries' collections are in copyright and from other countries.
Also, just about every academic library will lend journals from other countries. They may have paid a licensing fee in some cases, but this will add additional complication- and cost- to these practices. I'll need to think about this some more and visit some specific places to get a better grip on how this might apply, but I've little doubt that Jonathan Band was off on his analysis. He has worked with ALA and ARL for some time, and his work is pretty darned good.
If you read one of the sources of the original article- the one that expresses concern about protection for libraries- you'll find the Library Law blog and a post by Peter Hirtle. Peter Hirtle is very active in the area of copyright and libraries. He was on the Section 108 Group from the Library of Congress. He brought up the possibility that this court decision affects libraries' use of the 108 exemption. I take his concerns seriously.