Filing your taxes is free. Maybe you can spend $30 if you want to use turbo tax to do it for you.
Any job with these salary differences provides great health care and benefits.
Cars exist in Europe, I know many software developers there that have them. Why people pretend nobody has them if beyond me. And just like in the US, the closer and more convenient to the city center you are the more expensive it is to live there. Cars are also not as costly of a burden as they are in Europe. Also, most European tech jobs are in cities (London, Amsterdam, Dublin) that have similar cost of living to US cities which you don't need a car in (SF, NYC, Seattle). So it's mostly a moot point anyway.
Finally, we get to a point where there is a REAL cost difference: taxes. The overall burden of taxes will be 10-20% lower in the US, which is a substantial difference as it's a percentage on gross, not an additional fixed fee like many of the above expenses.
If you want to pretend all of that justifies a 6 figure salary difference, more power to you. I've looked into making the move many many times with actual figures and it never even comes close to being close.