If you’re still keeping up with The Big Bang Theory, which is currently midway through its ninth season on CBS, then you probably noticed something different about the most recent episode, “The Sales Call Sublimation.” As Reddit user specialkkurtis pointed out on the r/television forum, the episode was only 18 minutes and 34 seconds in length. Being that TBBT sits in a coveted half-hour slot on Thursday nights, this means that viewers were treated to a whopping 11 minutes and 26 seconds of commercials.
http://uproxx.com/tv/the-big-bang-theory-18-minutes/

I am an American who has lived in China the last 15 years and has come back twice the last two and a half years, and I find television now difficult to watch (and started a thread about my insight and complaints), and one is the excessive amounts of commercial interruptions. It is really ridiculous, and it doesn't do any good to try to watch two shows at once because there are so many commercials they run together. I find a lot of the commercials obnoxious too.

If I live in the United States, I would probably not even have television but use the Internet as my television. I know several websites where I can watch new shows (and frankly, I dislike literally 95 percent of them now) without the commercials, and stuff on YouTube. My folks pay over $100 a month for this crap and it doesn't even cover so called "premium" channels. And again, it is mostly crap!

Looking on YouTube, an episode of Amdy Griffith from the early 1960's ran 25 minutes. But also, there were less than half the population, and there was a near monopoly of three networks. There is so much competition now, hence more commercials.