And how many times have those humans - because they sure as hell weren't 'pilots' yet alone aviators - flown perfectly serviceable aircraft into a hill, an ocean or elsewhere because they screwed up, yet alone committed suicide and decided to take their passengers with them?
You've cited three examples of tech errors, and I'll grant there are likely many more - but "pilot error" outstrips technological failure especially these days, by an order of magnitude. A computer isn't going to shut down the wrong engine, like the crew did at Kegworth or Taipei. A computer isn't going to fly a 777 into a sea wall on a CAVU day that my 10 year old can (and does) land in and a computer isn't going to panic and hold full back stick while falling 35,000' into the Atlantic. There'll be new and novel failures but they'll still be rarer than the number of crew-induced errors today.
That being said....What scares me about the pilotless airliner is the same thing that scares me about those robot trains around the world. I'm paraphrasing here but, there are known unknowns - things we know we don't know, and there are unknown unknowns - those things that no one knows they don't know. And those are the things that are going to limit the introduction and deployment of autonomous airliners, because "It's not supposed to do that" doesn't cut the mustard when things go pear shaped in the flight levels.