I had doulas for both births (one hospital, one home).
I think the birth experiences in other countries does not compare at all. If you had a lovely experience in the Netherlands, its a safe bet that it was nothing like a similar birth in the US. There is a reason our birth statistics are shit.
I would argue that doulas save money over all- lower risk of complications like C/S, induction, pain meds, etc all result in a lower hospital bill, a faster recovery, a better chance of nursing, and they also provide nursing support after the birth.
Some dads are well equipped to be the birth partner. Most aren't, either because they just aren't, or because labor is too long for one person to be the support person for the whole 24+ hours. My H fell in the "just not a good support person" category. He doesn't have a lot of medical knowledge, he doesn't know much about babies, etc. He would never have thought to ask the nurse to get me a cup of ice water to sip on between contractions, or to put pressure on my lower back, or whatever. And the nurses aren't doing that stuff, at least not the whole time- they are charting and monitoring, and they have more than one patient. Plus, while he was hypothetically off getting me ice water, that leaves no one with me.
My 600$ included 3 before birth meetings, labor support, and 2 PP visits. Plus unlimited phone convos, and her being on call. Seems like a pretty good deal to me. For my 2nd birth, 2 doula friends did it for free. Around here, some hospitals provide them for all moms (they improve outcomes!) and especially for medicaid patients. In fact, in some states medicaid covers doulas because they lower birth costs overall, saving the state money.
Doulas are a great example of evidence based medicine. But that's cool, you don't have to hire a "butler" if you don't want one. However, maybe you should do just a tiny smidge of research before you form an opinion about something you clearly know nothing about.