That sounds like someone with very stupid money management. Unfortunately, this is probably the norm.
You're surely spending many hundreds of dollars/Euros per month to own and operate a private vehicle: loan, fuel, insurance, maintenance, repairs. If you go hiking every single weekend, that's 200 Euros (according to you), which still should be cheaper than owning a car. Most likely, you're not going to rent a car every weekend. So it should be pretty obvious that you'll come out way ahead if you sell your car and just rent a car for those occasional weekend hiking trips.
>I live in one of those european cities. ... We have public transport but its depressing and annoying and also expensive.
What city is that? The German cities I've visited had very inexpensive public transit, especially if you got multi-day (or longer) passes, which anyone living there probably would.