And I think this is the main reason Google Killed Google Reader. It was controversial (or illegal or ugly) to put ads over the third party content. And it was way better to have Adsense on the websites directly. Such "spring cleaning" was an alibi, not the reason. It was abandoned after some attempts to build a kind of social network inside, and probably they preferred people to create content on +1 instead of on blogs. But Blogger still exists, and there's a strong contradiction why to kill the reader for the blogs except one: Ads. Google Reader was bad for Ad business. And that's a big business in Google. And terribly sad.

They rely on ads to make money. Twitter could add ads to their RSS feeds, just as they add ads to their app feeds.

Some places that do offer rss only offer truncated feeds so you actually have to open the website and be monetized and fingerprinted. there are of course workarounds but its an arms race with only a few maintainers.