If everyone acted rationally yes. A good example of how we might make things worse is mandating that every structure have solar panels on the roof. Sure that might make sense in Arizona, it makes zero sense in Maine and other areas without sufficient sunlight, never-mind the implications for the grid.

Humans are prone to performative overreactions, because what works and what's emotionally satisfying to the masses are often two very different things.

Case in point: the ideological drive for electric vehicles. To ameliorate the greatest amount of carbon emissions as fast as possible we should be going all-in on PHEVs, because you can essentially take the one large battery in a single electric vehicle and chop it up to equip several PHEVs. Plus the batteries are small enough to charge overnight on a standard Level 1 outlet. Given that most people don't drive beyond a decent all-electric range (say 40-50 miles) each day, with PHEVs you get rid of something like 80% of tailpipe emissions from several people, which is a lot more than 100% of emissions from 1 person. And you don't need to build-out nearly as much extra electrical infrastructure or battery manufacturing/mining.

But let's not let math get in the way of all the talk about "half measures" and how PHEVs allow BIG WORSE-THAN-HITLER OIL to continue to exist, because obviously moral purity and Captain Planet cosplay is more important that the boring business of actually lowering carbon emissions.