I *AM* planning a HB, but it's not funded via medicare in all jurisdictions even in Canada - I was chatting with one woman in Alberta and it would have cost her several thousand dollars to have a homebirth. Some midwives are willing to do it, but they still need to be paid, and a lot of families simply can't afford that.
Here in BC we are very fortunate because most midwives offer homebirth services and it's fully funded by public health care. I will not be out a single penny (except for some supplies) for my homebirth. But I think that BC and Ontario are the only places in Canada where this is the case (please someone correct me if I'm wrong). This makes me very sad and annoyed because I think homebirths actually save a lot of money (no overhead on hospital supplies, nursing staff, etc. - all the health care system has to pay for is the midwife's fee) and our public health care system is so overburdened that all the provinces should be making cost-saving decisions wherever possible and this is one that would actually HELP people!
Now, in the US - I would imagine that there are a pile of reasons why you wouldn't be able to have a homebirth. It's still actually illegal in several states, right? And if your birth were otherwise covered by insurance, but not if you gave birth at home (similar situation to Canada) I could see finances definitely getting in the way. Also, a lack of qualified or willing midwives, or even pressure from family to have a "safe" hospital birth...
Basically the problem is that birth has been medicalized for so long that it will take some time before people accept that home birth should be the *norm* not the exception.