Sorry for the sarcasm, but I've heard this stuff before, Some years ago, I replaced my oil furnace and re-insulated my house. I had a good oil furnace, and replaced it with one of the 99+ percent gas furnaces. Pretty cool, they extract so much heat from the gas that the "chimney' is a piece of PVC pipe. The house was already insulated well, but I put some more in the attic.
Today? Well, that payback is interesting stuff there. The folks who took your argument failed to see how the price of oil would skyrocket, (and after a lull, its heading right back up there) Many of these smart folk are paying per month, what I pay for the entire heating season. Plus they are keeping their houses rather colder.
In addition, the house is warmer, with much less dust and grime accumulation, since oil heat is friggin' filthy, and the furnace doesn't use half the electricity for the igniter and blowers, which means I don't need as large an emergency generator to keep warm, although in my case, it frees up power for other uses, since I already have it.
Warmer, cleaner, cheaper, and using real life costs rather than assuming everything will stay the same, I improved our quality of life, as well as turned the "payback" into a couple years. The other parts were worth it by themselves, even disregarding the money involved.