Let's see a few of the major events relevant to our discussion:
2013 is the year Google decides to sunset Google Reader, a (if not the most) widely used web feed aggregator (for RSS and Atom feeds);
2013 is the year Google decides to close XMPP server-to-server federation in their Google Chat service; Facebook will to the same with their Messenger product the following year;
2013 is the year Google first proposes the removal of XSLT, a proposal that is so unpopular that it will continue receiving comments against it as far as 5 years later (the last comment in the thread is from 2018);
That's a rough year