It’s covered in Spain. Many people still choose to go “outside of Social Security” but medical is medical is medical and hereabouts a dentist is an MD (the official name is estomatólogo, but they use dentista because well, most people go for a look at their caries and not at their stomachs). The “outside of SS” places have payment plans and you know the cost up front.
And yeah, it looks very strange but not any more strange than the notion that losing your job or needing major surgery can throw you from middle class into food coupons. It’s just a different world.