My case is very similar, when my son goes the name ends. If he nor my daughter have offspring then the family ends as well upon their passing. They are adults now and show no interest in the existing family graves. I feel me and my wife's passing will not change things in that respect much. Like mentioned before most of my friends and classmates are in the same boat having moved away or died off. I don't feel anyone is going to come and look for my grave nor my wife's so that is why I had considered cremation. Since that isn't doable any longer I will end up "planted". I intend to get a large headstone w/o the vases because there will be no one to maintain them. To me a cemetery is just a junk yard for old worn out bodies but like you guys have said "it's for the living, not the dead". I don't want to be strung up like Mussolini but once dead it's not going to matter much how our families arrange the farewell.
Since funerals ARE for the living, if you are considering cremation you may want to discuss it with those who will survive you, not just your wife but your children. It may be all too upsetting for them.