What happened to Slashdot wasn't a "consolidation", though, it was a suicide. I was a heavy reader of the site up until they had an infamous redesign that made the site literally unusable for me, so I left.
That's very different from the scenario discussed in the article.
It is an interesting case study. Most designers would not think that they can tank a site.
I don't think that was it. Slashdot would only run stories from their 'content partners' like ZDNet and the Register, so they were always 2 days behind Reddit/HN/Twitter/etc.
(When RMS was 'cancelled', that would have been a huge deal there in the old days, they had one post days later.)
Also Digg wasn't just a graphical redesign, they changed how the site worked. I don't think Slashdot ever did that.