The perspective of this article is all topsy-turvy. It makes it sound as though these groups are something owned, or at least "managed", by Google, which also "happen" to be available by other means, when the reality is of course that these are usenet newsgroups, well older than Google, older than the web, and available from any usenet server (such as, for example, the appropriately named Eternal September, or you could even set up your own).
It just so happens that, once upon a time, a company called DejaNews decided to start permanently archiving usenet (which, up until that point, had generally been ephemeral, with usenet servers generally only storing the posts from perhaps the past few weeks, or perhaps months, before deleting older ones), and eventually Google acquired DejaNews and the newsgroup archiving service. If Google are failing to manage their newsgroup archive properly (no surprise), people can still participate in newgroups using a newsreader program in the traditional way , as usenet is, of course, a distributed service. Maybe for a historic archive of usenet, those who are interested should perhaps get together and set up an alternative archiving service, as Google don't seem to have sufficient interest to do it properly. I would have thought that it would be the sort of thing that the Internet Archive, or a similar organisation, might perhaps be interested in.
 although, to be honest, with the relentlessly increasing spam levels, the sharp drop-off in new usenauts since about 2000 or thereabouts, and the minor and moderate technical hurdles of having to know how to set up your newsreader and manage your scorefile/killfile effectively (slrn FTW!), respectively, it is (sadly) definitely a dying medium. But it always surprises me when I pop in occasionally that some groups somehow do still manage to maintain a good core of posters and sensible and interesting discussion, even nowadays.