Do you think fuel efficiency or emission standards "slowed down innovation"? They brought a huge amount of innovation: lighter materials, better aerodynamics, higher compression ratios, direct injection, better mixture control, etc.
There will still be innovation; the solutions will just have satisfy the new parameters.
And then when EVs become viable they went - naaaah look at those efficient diesels!!
To a degree.
You can’t have infinitely improving standards for an infinite time, otherwise you end up with bullshit like Dieselgate, and ecotechnocrats forcing everyone to drive around in mobile inextinguishable incendiary devices.
Yes, they definitely slowed down innovation and decreased consumer surplus compared to the counterfactual of just taxing the behaviour you don't like (like taxing fuel or emissions).