Suzy Welch has long considered the Upper East Side home. The author and business commentator—whose late husband, Jack Welch, led General Electric for two decades—moved into her 40-foot-wide East 81st Street mansion four years ago and quickly embraced everything that made the block special—its tree-lined calm, its unusually deep rear gardens, and its quick access to her favorite neighborhood institutions.
“I’ve always lived on the Upper East Side. What other part of New…

