I know a man who's STI stopped working on PBP 2003. Had to ride a few hundred kilometers of hills before he got to a control that could fix it. I was riding on a 300k brevet in 2000 when an STI broke for a friend. Man had to ride the second hilly half with just the front working. I ride with a man who has replaced several STI in the past 5 years due to them not working anymore. All these STI are 9 speed. And I have Ergo shifters that needed a new spare part, easily replaced by me at home after ordering the part. And occassionally my Ergo sort of freezes, the thumb button does not pivot on and off the ratchet ring like it should. Rust and gunk can cause this. Can be fixed by removing the rust/gunk or replacing the thumb button. So both STI and Ergo fail, stop working. Whereas my 1991 bar end shifters had to have the rubber lever covered glued back on in 1992 but that is it for repair.
Only my loaded touring bike has bar end levers. My other geared bikes have Ergo. Its more fun, enjoyable, better, etc. despite the extra potential of not working every now and then. If I was touring in the remote parts of the world, I'd go for bar end if buying new or cheap. If touring in the developed world, I'd go with STI/Ergo if buying new. But since I own a loaded touring bike already, I won't waste money replacing the bar end shifters with STI/Ergo.