Even with registration fees, it is still negligible. Forbes has a complete list of U.S. states that charge added fees for plugin vehicles. It is usually less than two fill ups.  Considering how quiet and clean EVs are, I expect that health care savings will be sufficient to cover the lost road taxes, the same way public transport is.

With a 2015 Nissan LEAF, I'm saving $60 per week in gas. So far, that's $6,000. More than enough to replace the battery. But that is very unlikely. It has a 6 year, 100,000 km warranty against capacity loss - not just failure. The new LEAFs and most other EVs have 8 year, 160,000 km warranties or better. That surpasses most ICE drivetrain warranties. I'm pretty sure the bean counters made sure that there would be few if any claims.

https://www.forbes.com/sites/jimgorzelany/2017/01/11/more-states-charging-added-fees-for-plug-in-cars/#45b0f3b22740