Indeed. This is a thought experiment libertarians often suggest. Just substitute "The government should ..." with "We should send men with guns to people's homes in order to ...". A bit hyperbolic maybe, but a useful lens.
I'm just guessing at the exact chain of enforcement, but I think we both agree, ultimately it comes down to the state's capacity for violence. However, that doesn't mean that when we pass environmental regulations we should envision people being dragged from their homes screaming in the middle of the night at gunpoint while their children soil themselves and are traumatized for life. We should envision what actually happens: companies keeping their emissions within legal limits and paying fines when they fail to do so. We should think about the reality of what enforcement will actually look like, not imagine the bank officers in solitary confinement for struggling with prison guards and their children in therapy for PTSD.
I agree that we should keep that stuff in mind when that's the reality of enforcement. Drug laws, for example, do result in a lot of young kids seeing their parents and siblings dragged out of their homes at gunpoint. But I think it's a misleading image when talking about most government uses of power.
Companies generally follow the law because it's very expensive not to, so much so that it hardly feels like coercion, as you explain. They basically agree that they should act a certain way, which is good for everyone, to be sure, but it's not like they could choose to act a different way. As you say, if they actually refused all the way to the end, they would be dragged off to prison, and we wouldn't necessarily feel bad for them, because the pollution they visited on the surrounding community would be real and terrible. But I think all this illustrates is that sometimes coercion is justified, and where it's very justified, everyone more or less agrees to go along, because people know that they would be dragged off to prison AND look like jerks. I don't think it illustrates that the system isn't that coercive, though.
I think this view of coercion is rather like people consuming more meat because they're so far removed from the slaughterhouse. When you're in a McDonald's, it really doesn't feel like an animal died for that hamburger, it's just another thing to eat.
Likewise, when most people follow the rules to the extent that it doesn't feel like coercion, we forget just how violent the system is to people who refuse to go along (and like I said, that violence may be justified, but the threat of it is never absent).
Edit: I feel like we have been taught that coercion is always bad and never justified and so we want to do mental gymnastics to convince ourselves that what we're doing isn't really coercion, and I think it would be healthier for us to acknowledge coercion where ever it happens and also acknowledge when we all believe that we have found such an obviously correct policy (like no toxic pollution) that not only is coercion appropriate, but any sort of resistance to coercion would be seen as ridiculous. This acknowledgement has the upside of forcing us to be fully aware of the thin line we walk between a fair and just society and a violent and oppressive one.