this just means you can't purchase, borrow, or download new content for those devices through Amazon. And this was already the case for all the Kindles that don't have wifi, since they killed the "download & transfer via USB" option last year.
I'm sure the thought is that people will buy new Kindles - and I'm sure many people will, especially with the confusing way this news is being shared. But pre-2012 Kindles still work, just with no reason to buy books from Amazon. Seems stupid to me to turn away all the people that want to keep buying books but don't want to buy a new Kindle (and really there's several reasons to not, some of which might be accessibility issues for some people; for example they replaced the text-to-speech feature with a pitiful, cumbersome screen reader after they bought Audible), but I guess they're counting on people not being able to figure out they can keep using them.