Drop in barrels are good for a combat gun but tolerances have to be loose enough to fit any gun so top accuracy is not a given. Yes it happens but not guaranteed.
Not true with the Storm Lake barrels which I am really satisfied with. First time I did it with a USGI Colt 1911A1 NM, it was tight and worked nicely. No it's not a match grade barrel, but it sure keeps up with any normal barrel as well as the old Colt NM barrels.
Polishing an unramped barrels can be bad if not done by an experienced individual since polishing can be good but removal of too much material can ruin a barrel quickly.
Frames are also easily ruined.
I have always run ramped barrels in my 1911s but they are used for competitive purposes and sometimes high pressures must be used(well over posted maximums)so a fully supported chamber is safer.
You can have a fully supported chamber on both ramped and conventional barrels. Since the early days of IPSC, Irv Sr.'s BarSto barrels were the go to barrel for competition and still work nicely in both 45acp and 38 super for the race guns.
Worst I've seen were novices that "polished" the feed ramp on a conventional "Match" barrel to the point where the cases were failing by the head because it was no longer supported. In those days were ALL loaded hot because of the old IPSC power factor.
Worst I've seen with "Pressure" was when someone touched off a triple charged round. bulged and slit the barrel, bulged the frame and slide. Believe it or not, it did get fixed although I wouldn't have. It's also why I like 231. When I was a novice with a Star, I did load two doubles... cost me 2 sets of grips and 2 magazines.