These 30-35% wood savings are proven where?
There are 1.25 million posts on this site. A damn good portion of them are from folks who have actual burning experience with both types of units who are surprised with what they gain when they switch from one type to another. I am one of those folks. I LOVED my fisher stove, but due to deterioration of my chimney, I needed at add a liner. I didn't have enough room to install a liner large enough to feed the fisher, so I had to let it go. In doing so, I was surprised to find that my switch to an Englander 30 changed my wood consumption from 5.5 to 6 cord a year down to 4-4.5 cord. I also found that the chimney stayed cleaner and the stove held a fire and coals longer than the fisher could. With the fisher, on cold winter days I'd come home to a 60 degree house and be able to get it up to 70 within an hour. With the 30, on a similar day, I'll now come home to a 65 degree house, but it still takes the hour to get things up to 70. In other words, after trying things out, the only advantage the fisher had was that it could heat things up quicker if necessary, but since the new unit hold a fire longer, that isn't much of an issue.
I'm certainly not a hater of vintage stoves, I just like to make certain that folks considering one are well informed. While I have a modern stove in my home, my cabin still uses 2 vintage stoves (a timberline and an atlanta huntsman which I just restored
https://www.hearth.com/talk/threads/atlanta-huntsman-hunting-camp-project.92569/ to replace our worn out atlanta homesteader) and I also operate several non-epa units (kalamazoo cook stove, fisher mama bear, double barrel stove) at other locations regularly and I have no plans on changing them out as they do all we need there, and efficiency isn't as important, plus I'm just plain nostalgic about them.
As far as the Florida bungalow syndrome, it happens in some cases simply because of the type of chimney found on the home. Dealing with it is no different than one person running X vintage stove and needing a chimney damper because of their draft, while another person using the same unit on a different chimney doesn't need that. That is simply an explanation for the observations that some folks have found. No need to make a mountain out of a mole hill.
At the end of the day, to answer the OP question, I had to switch to a modern stove due to the chimney and have been happy since then with doing it as it had many benefits. However, I WAS very happy with my pre-epa unit. Had my chimney not been the deciding factor, I would still be running that fisher and not knowing what I was missing as it did do the job honorably.
For my cabin and other places that I still use vintage stoves, they do the job and a change simply wouldn't gain us anything in those locations considering the usage.
For the average burner, I think many folks simply figure if it isn't broke, don't fix it. If what they have does the job safely, then why change when there are so many other things to spend money on. I keep 2 older vehicles around for the same reason. Sure I could get better gas mileage with a newer unit, and other benefits, but they are simply too solid to give up and as such I accept and am willing to pay for the inefficiency. At least for the time being.
pen