I think you are overestimating it. Because you overestimating the degree to which the present legal context is similar to when DeCSS was an issue, and because you are underestimating the degree to which the financial and political power imbalance between the xxAAs and the other side was key to the effect then, and because you are misunderstanding who is doing the thing this most effects, before countermeasures (its not the easily deterrable parties), and because you are (based on the circumvention POCs) overestimating the degree to which any controllable specialized circumvention tool is needed to circumvent this type of “protection”.
I agree that power imbalance is a significant factor that is different. Fair point.
Why would these parties not easily be deterred by legal concerns? Well there are a variety of groups in this space, many of them are corporate/start ups, and usually they are more adverse to legal risk than your average pseudo-anonoymous citizen.
That's a big if. Sure the librarian of congress could justifiably issue an exemption, but i think it is far from garunteed that they would.
I think you are underestimating what a cooling affect FUD related to anticircumvention could be. Just consider all the stuff related to dvds that went down back in the day e.g. Dmitry Sklyarov being arrested at defcon (even if it didn't stick). The uncertainty could definitely have a major cooling effect.