First of all I disagree that it's difficult to get injunctions to stop an activity that was illegal from the start. In fact, sometimes environmental reviews can backfire because they typically require affirmation by the government, which can create a defense to doing something that would otherwise be judged illegal. That type of loophole is why people are so cynical.
But even so, how does the song & dance prevent any of that? It's not like, e.g., a battery manufacturer submits a plan admitting that they're gonna dump stuff.
The plan details how those chemical storage tanks are designed and constructed. The monitoring, in place, the contingency plans.
It raises the stakes, Obviously they can still cheat but now it's a matter of criminal negligence not civil law.
Sure, but in terms of expenditure and especially time (and time is a huge expense because of the cost of raising and securing financing) that work doesn't make up the bulk of the cost. There's nothing wrong with impact statements themselves. You need independent assessments of hazards beyond the well known ones like chemical storage, where in most cases existing codes and regulations are more than adequate. It's that in many places, California especially, there's no fixed goal post. The review process has effectively become a vehicle for local and even national politics to play out. And a method for detractors to spread FUD (again especially in California where anyone, not just officials or local residents, can challenge and drag out review of an impact statement itself, let alone proposed mitigations). Just look at what has happened with CaHSR (they're still not completely done getting write-off on all the necessary impact statements for the planned route) or the politics involved with approving offshore wind farms, where Trump and, to a lesser extent, the Biden administration showed how much pure politics plays into things and drives costs up. (And federal EIP review process is, at least historically, much simpler and less subject to political games compared to some state analogs.)
The maxim, "a nation of laws, not of men", is applicable here. If you don't have fixed goal posts or rules, governance becomes chaotic, not to mention unjust, inefficient, and ultimately corrupt (so many people like Trump because he promises to substitute his own judgement in place of democratic processes).
It would be nice if we could comprehensively hypothesis and address every possible manner in which things could wrong, but we can't. Most of the time you need to rely on broad rules, at least as a catchall, like don't harm someone or don't pollute, and ensure fast, consistent, and efficient accountability when injuries occur. The current state of development approval has become grossly degenerate in many places. In others it could definitely use some firming up. But let's not pretend that a project in California would get away with most of the stuff they can in Louisiana just because we reformed the review process. For one thing, California is much better about enforcing existing hazard codes at both the planning approval and operational stages.