You are giving up literally millions of dollars by living in Europe. No amount of free healthcare makes up for the gap. By the way, healthcare is low cost / essentially free at most tech companies in the US.
If you have any serious medical issues, you carry your own insurance. Luckily, the salary generally makes this feasible.
I've never seen this at any tech company in the SFBA. They cover 100% of the premium for yourself and it's only <$200/mo to cover a whole family of dependents. Their plans are always among the best. Copays are the lowest by far of anything I've ever seen, including ACA marketplace plans, my parents' plans, school offered plans, and non-"tech" company plans.
$200/mo is way, way less than I pay in taxes to CA state alone.
> since I prefer Kaiser
Obviously if you want Kaiser and they don't offer it you have to buy it yourself. Personally I don't feel like the difference is too huge that it justifies buying insurance myself. I used to have Kaiser and you get slightly smaller delays (3 days instead of say a week) to see specialists and that's it.
Don't get me wrong, there are many good things about the US (e.g. networking opportunities, better availability of new tech, VC for startups, freedom to do things that just aren't possible in Europe), but OTOH, it's much harder to find safe walkable neighborhoods, excellent public transport, solidly built houses, and in San Francisco apparently human feces are a problem because of a homelessness crisis.