This line of thinking - both paragraphs - implies no responsibility on the part of the passenger whatsoever and that, in some way, is the heart of the problem.
No it doesn't. I don't imply anything. If I think something I say it directly, don't fall into the trap a lot fall into on this forum and read more than what's written. I choose my words carefully.
Some people don't take their responsibilities seriously, but we know that's true, hence fare evaders.
I'm sure some people are frightened enough by seeing others caught to start buying tickets, but I would suggest most evaders aren't.
It's easy to sit there and say "passengers should know their responsibilities" as if that solves everything but we live in the real world. If everyone took their responsibilities seriously you could do away with all revenue staff and just have a big bucket of money at the entrance to each station (together with a card machine) for people to sling their fares into and take their change out of. However, we know that TOCs would go bankrupt in days if they did that.
There will always be people who try to evade fares. However, TOCs will always choose the method of enforcement that brings the most profit, not the method that leads to the most people paying, because they have to.
It's possible that getting the most people to pay (which is the ideal) is the most profitable route, but we know it isn't or the TOCs would be doing it.