I seem to recall reading that his assertions were never proven, but I can't find the reference. This article is somewhat dated, but it is interesting to see how some things have changed and others have stayed the same since Papert wrote this. I'm sure there are many teachers who use MicroWorlds with their students, but I don't know who they are.
Logo is still there.
The Internet has caused things to change drastically since the 80's, but there are still critics who harbor these same fears. The truth is, communication via computers has caused the nature of many human associations to change, impacting schoolchildren and adults alike. Many teachers fear that their students will have too much in the way of human associations, for example in using AOL Instant Messenger or wireless handheld computers during class time. Again, I am lucky to enjoy a boss who seeks out ways to include these tools in school, even while I hear my cadre mates telling me that AIM has been removed from their machines. In that article, Robert Tierney describes the unexpected effects that a technology-rich environment provided for students in the ACOT project.