I have watched all of the Cup matches back through 2012. In those 11 years, no one has won from a 4-game deficit. And only 6 matches have been won from a 3-game deficit:
2022 -- Shaw defeated Strickland 5-3 after trailing 0-3
2021 -- Alcaide d. Kaçi 5-4 from 1-4
2019 -- Kaçi/Kazakis d. Woodward/Styer 5-4 from 1-4
2019 -- Shaw/Feijen d. Bergman/Thorpe 5-4 from 0-3
2013 -- Souquet d. Hatch 6-5 from 1-4
2012 -- Archer/Shuff d. Melling/Van den Berg 5-4 from 0-3
I watched many of the matches in 2010, including this one::
2010 -- Appleton d. Hatch 5-4 from 0-3.