Totally appreciate that— I have kids myself in the same age range, and we've taken lots of trips together by bus, subway, and regional rail, so I do hear where you're coming from. At the same time, the road access and parking facilities that you need to exist at your destination in order to be able to drive door to door do have real costs, and those costs aren't borne by the person who drives in a few times a year to visit.

I suspect that there is probably a sliding scale of mechanisms by which you could trade money and time/convenience back and forth on this trip— for example, paying more to park closer in to the city (shorter transit trip) or transferring to a cab and paying the cab (instead of transit) to get between your parking spot and destination. You haven't previously had to consider these options because the default one was so obviously the cheapest and most convenient; maybe that's part of the value of cities drawing a hard line on this, that now everyone who previously just drove by default now really has to consider alternatives.

Anyway, I really do respect Oslo and other cities for giving this a try— despite the inconvenience to people in your situation, it'll be neat to see more of what else comes of it.