Most people on the planet cannot afford the time and money to change their lifestyles to be environmentally-friendly. And among those few who do, most have other priorities. It is naive to believe that a collective change in consument behaviour will scale up as the solution to Earth's environment problems.
I don't think the parent commenter meant the producers of goods as the "people with actual power". It is just as unreasonable to believe that businesses will suddenly start caring about environment, since that would put them at a disadvantage on the market. (Though I imagine the whole narrative that it is the consumer's responsibility to fix the environment is very convenient for some of the less-environmentally friendly corporations who might be afraid of additional burdens on them so there's an incentive to push that message)
In my opinion the root of the problem is that damaging the environment is not associated with an inherent cost. In my opinion, scalable solutions are those which "use the free market to regulate itself", i.e. things like carbon taxes (to make CO2 emission a cost), shifting cost of garbage utilisation to packaging producers (to make non-recyclable packaging a cost) etc. (+ corresponding change to social programs to lessen the impact of this change on consumers who would not afford increase in the price of goods). But for this to happen there needs to be a political will. For this reason I think that the most environmentally conscious things those of us who live in democracies can do is to vote for environmentally conscious representatives who understand the issue well.