Look, everyone who advertises wants one thing: your money. These people are no different than any other business using advertising. If you go to an athletic club, most want you to sign up and pay them, and if you get in shape, then that is a swell deal too, maybe you will refer people to them.
This P90x web site said that muscle confusion is "new". So yes, they do claim that it is new, if not that they invented it, and the way it appears, an uninformed reader will read what they wrote as they invented it. Yes, it may work for some people. No, it is not necessarily the answer, not long term. As you stated, you have so far remained "motivated" for four months.
That is the real key here, motivation. Lots of people "want" to lose weight or get in shape but they lack the motivation to keep the intertia going past all the low spots in life that inevitably come up from living life. That is the main ingredient, along with what lots of people have shared here about "doing work" and making major changes in how you eat, trying types of exercise that is different than what you are used to (like Yoga), taking in less calories day after day, etc. If you are not willing to do whatever it takes to reach that goal of fat loss and better fitness, and make it a life long change, it won't happen whether you sit at home watching DVD's or you get off your *** and go to a gym and hit the iron and the cardio.