Cambridge is full of old houses, and on my daily walks I see renovations all the time. Pretty much nobody rips out all the old wood framing or wood boards and keeps one random exterior wall —what you’re describing is the exception, not the rule.
For a 100+ year-old house in
desirable location, the typical renovation is
systems + enclosure + kitchens/baths, plus
selective structural repairs where needed—not a full replacement of the wood frame. Most projects keep the structural shell, then modernize electrical, plumbing, HVAC, insulation/air-sealing, windows/doors, and finishes. Ofcourse such houses cost much more than new construction