Can you provide a couple of examples? I assume you mostly mean instances where the isolator was closed and a diver breathed the whole tank down. I could argue that these were diver error and complacency—not checking tank pressure even one time 5-10+ min into a dive. As a friendly debate, I’ll give you these “manifold” failure deaths, but then I get the sidemount roll-off deaths—starting with the one in Peacock a couple of years ago.
I’m one of those right tool for the job guys, but I will admit SM has a purpose and is a necessity for certain divers. The one argument I won’t accept is that SM is EASIER off a boat. Manageable, sure—equipment lines, bolt snaps, etc, but BM anything is easier, especially in rough seas.