> If this is correct, tax policy is a huge distraction, and if governments really want to jump-start growth they should be funding basic research, ensuring that the results are public (to their citizens, at least), and encouraging bright young people from across the world to immigrate to their jurisdictions.

Which could be accomplished by raising taxes.

Raising taxes, particularly in the US to pay for social services like healthcare and education would also have a huge effect on growth and productivity. It's not really the level of taxes that matters it's that you spend money on things that enabled people to pursue innovation/employement/art/etc and not get burnt out on administrative bullshit and constant stress from preventable things.