That's a really good point. I am the author of the article, and this is something I debated during writing. In the end the goal was to provide an "in-depth enough" tutorial on adding speech recognition to an app for people who were new to it and possibly intimidated by the topic. For that, I think SpeechRecognition is a fantastic module.
I had to leave a lot out of this that I wish could have gone in, simply due to length constraints. In that regard, perhaps "The Ultimate Guide to Speech Recognition" wasn't be best choice of title. I'm sure that we'll be updating this article as time goes on, and Google's streaming API is something I want to make sure goes in it.
Also, something that was left out of the article was SpeechRecognition's listen_in_background method, which does solve this problem somewhat. My issue with it is that SpeechRecognition uses a somewhat crude RMS energy based VAD for detecting speech.