Disagree that improving batteries was ever popular vs wonkish. Definitely disagree that average climate change advocates discussed this.
I went to college in 2012-2016 at a liberal arts college (emphasis on liberal, folks certainly cared about climate change). I can’t recall a single conversation about working on battery tech. I can recall several on geoengineering & pumping white sulfur into the atmosphere.
The Laffer curve sloping downward (once past the optimal tax rate) does not require agents entering a shadow economy. It is very much possible that agents merely choose not to work, as the cost of marginal effort is not sufficiently rewarded with enough marginal income.
So in the specific example, there is no guarantee some secret agent must emerge. Higher tax rates merely increase the incentive to avoid taxation, they don’t guarantee malfeasance.