In most of these cases, the companies involved did NOT follow standard security practices.

I am pretty sure that is what people mean when they say "held responsible", they mean "held responsible for failing to follow standard security practices", not for the actual act of getting hacked.

Is that really the analogy you want to use the bolster your argument? Licensing was forced on the medical profession because of rampant quackery causing a large number of deaths. Some of the horrors that went on before enforced medical licensing are well-nigh unbelievable, e.g. https://en.wikipedia.org/wiki/John_R._Brinkley

But even if they do everything right, is it really fair to let the companies just shrug their shoulders and say "it happens"? While their users are the ones who really get hurt.

I like this analogy, but deaths shouldn't be the leading indicator just an indicator. Family member had a surgery with well known procedures, say removing a gall bladder. Unfortunately, this surgeon skipped a step in lieu of setting a record for fastest procedure. Because steps were skipped, the gall bladder was not scooped into a net to avoid spilled gall stones which resulted stones spilling into the abdominal cavity requiring numerous follow up surgeries to remove the spilled stones as they made themselves known. So clearly not following accepted procedures should be a clear win in a malpractice case, yeah? Wrong. No doctor would testify against the surgeon and the case was dismissed. I feel like this is exactly how it would work in software security incidents as well.