> This despite the fact that we have lots of experience of programs running on computers that produces wildly inconsistent outputs.

The average user has very little. A word processor with inconsistent pagination or a spreadsheet with inconsistent totals is rightly seen as faulty.

Yeah but daily tools have lots of complexity which appears as non determinism (if we are thinking only UX, not actual determinism). For example, try moving an image in the word doc. I have been using MS word my entire life it seems, still don't know what the rules are lol.