The latest victims are the small CMS vendors who have been selling proprietary CMS solutions to public school districts for the past 15 years, charging far too much money (your U.S. taxpayer dollars!) for barely functional CMS's. The FCC voted recently to prohibit spending federal money on these solutions, a practice that basically created the market, so now every school district in the U.S. (14,000+) are looking around for cheaper and better solutions. A large percentage of them are migrating to WordPress.
E-Rate is a major funding source for school Internet connections and is ran by the FCC. The sidebar on that article says:
"Phases out support for some non-broadband services, such as voice services; and eliminates support for others, such as email, Web-hosting, paging, and components of telephone service such as text-messaging and directory assistance."
I'm guessing it relates to that "web-hosting" bit.
You can read more about the FCC's E-Rate Modernization Order :https://www.fcc.gov/page/summary-second-e-rate-modernization...
And most schools I know are migrating to Drupal.
The exception is the higher education market (colleges and universities), who are choosing Drupal over WordPress.