if they detect browser plugins through some public ID - how difficult is it to change those?

I actually dismissed that one from the get go since there is not confirmation of any mechanism they described in the article. Not going to spend time on technical-looking explanations from someone who calls a whole another extension a "workaround". Might as well be the case of broken or outdated filters in ABP.

I'm sure if some major site finds a way to know your extensions we'll see some major unsolvable issues.