Yes, the people could care more and could stand up for it, but it's so easy to blame them and that's exactly what the corporations & politicians want.
It's not the "corporations"[1] keeping you from that six pack, nor it is it keeping you from building a single payer healthcare system. Not wanting to put in the toil to make it happen will certainly get in the way, though. We all understand why nobody really wants to put in the hard work and suffering to make the necessary changes, but that doesn't change the fact that it won't happen until you do it.
[1] Which, in this context, is just another way to say people. And in this case often the very same people. ~40% of US corporate stock is held by Average Joe retirements savings account (IRA, 401k, etc.). Ask these people if they'd like a single payer healthcare system and the answer would almost certainly be "Yes!". But if you then ask them to do the work to see it through: "Never mind. What we have will do.".
Being generous in assuming you mean while remaining in the USA: The Amish are quite prevalent in Pennsylvania, Ohio, and Indiana. They've already done the hard work. Joining them may take some small amount of personal sacrifice, perhaps — there is no such thing as a free lunch — but is quite doable for someone who wants it. Like the six pack, all you have to do is jump in and do it.
Alternatively, you can produce your own metaphorical weights and food supply that is to your exact liking, but that is obviously going to take singificantly more input for you to setup and is going to be heavily dependent on other people to buy into your exacting specifications. This route would not allow you to just jump into building the metaphorical six pack at your leisure. It could take many years before you are even able to first produce weights/food, let alone starting to apply them to your six pack journey. But the best time to plant a tree was 20 years ago, as they say. It will never happen if you don't do anything, that much is certain.
No, I think its referring more to the systems that describe how the group of people behave. It is an important distinction.
Also, the idea that effective and lasting change requires significant personal sacrifice and enduring hardship is yet another thing that corporations and politicians would like you to believe. It's great for causing inaction through human nature. Its effectiveness can be seen in anti-riot measures like tear gas or less-certainly-lethal munitions, asking people the question of "do you believe enough to endure THIS?" It's a rhetorical question.
