Everything changes, but people like to believe that they what they trust has not changed for worse. Apps are bad to judge they change with each version.
Defender sucked for years then it got better, then it got worse. Like Outlook, it was bad, Outlook New was actually pretty good, now it is a sucky webapp.
As for AVs, Spybot was great, as well as Ewido or Superantispyware, now they are gone, Panda, Kaspersky and Comodo are currently in a huge free fall.