When the actual policy implementation is revealed and people see how it will affect them, they realize it's not free of trade-offs and downsides.
For example, higher taxes and higher gas prices will make a lot of people drop support for climate policy.
As the voters in each state also choose who they send to Congress, we end up with a legislature that reflects the state-by-state preferences of the voters rather than the results of a nationwide opinion poll.
Polling the American population as a whole, when support for these policies and congressional representation are determined on a state-by-state basis, is not that useful.
If we could get more direct voting on these policies, it is quite likely to be quite different outcomes from the representatives chosen by primaries dominated by fanatics system currently in place. As someone that grumbles constantly at all the technically complicated ballot initiatives I have to wade thru in CA, I would prefer a system where the elected representatives shared the values of the people they represent, but maybe the internet has rendered that impossible.
Just because people want solutions to these problems doesn't mean they will support stupid or wasteful policies to address them.
> For each policy, we asked participants to estimate the percent of Americans who would support it. Our list of policies included support for a carbon tax levied against fossil fuel companies and redistributed to Americans through tax breaks. The list also included a renewable energy standard that mandates 100% electricity generated by renewable energy in the near term—an essential step in decarbonizing our energy production34. And, as decarbonizing our energy infrastructure will require rapidly siting of wind and solar across the US, we also included support for siting renewables on public lands34. Given the need to consider infrastructure, jobs, and social equity in transitioning to renewable energy, we also asked participants to estimate the support for the Green New Deal (GND). Notably, large environmental policy packages like the GND and the American Jobs Plan may play a key role in passing environmental legislation, as research shows that bundling more redistributive, social equity, and job-creating measures into major environmental policies makes them more popular35
The reason the votes don't materialize is that we don't have direct democracy and voting is a complicated and imperfect proxy for measuring support of any single issue. Candidates are a mixture of party, identity, and policies.