For example a person could sit around and light barrels of oil on fire and create legislation that changed the incentives regarding energy production (which we already do a lot of and is one of the only effective things we do at scale to affect climate outcomes) or that bans or changes costs for plastic production and still come out leagues ahead in terms of having changed things for the better.
Sure if you are publicly announcing that you are lighting the oil on fire, no one is going to take your legislation seriously but the reality is there is no good source of record keeping on people's day to day behavior unless the consciously expose it so you could simultaneously live a horrificly environmentally unfriendly lifestyle and improve things.
My point is not that you should do this, but that the idea this change is going to swell from the ground up is nonsense. It needs to come from well organized legislation. That piece of legislation is probably not going to be much affected by the individual track record in the hundreds of people who end up being involved in its production.