I don't have a high enough level of a vocabulary to express just how good this is and how much I love your more in-depth, critical analysis of Bruce and Jason as well as them operating the same issues from opposite ends of the power balance, so instead I'm gonna ramble like a madman for a second about a few specific parts from your analysis (if you don't mind!):
Something interesting that you brought up was that where as Bruce could, in theory, walk away from being Batman, Jason can't walk away from the experiences that shaped him as a kid. Jason grew up learning how to survive; not necessarily how to flourish, but how to scrape by and keep himself alive even if it meant a trail of lost teeth or blood in his wake. He has this core understanding that sometimes in order to survive, you have to do bad things to keep yourself from ending up six feet under or in a gutter somewhere.
And I think that's the saddest thing for me when I look at how Bruce carries himself as if he's above that, as if he believes everyone should adhere to this morality that he has that very much comes from a place of never really having to fight for anything in his childhood. I'm not saying Bruce didn't struggle, but in terms of basic survival? Bruce always had someone (Alfred or even Leslie Thompkins, for example) or something (his family's wealth and their home) to fall back on in those times. But then you compare that with Jason, a kid that grew up in a low-income, crime-riddled part of Gotham, where there were only a handful of ways to get by and at least half of them were illegal (i.e sex work and drug-running), and you really see the difference between them like night and day.
Bruce witnessed a single murder. Traumatizing, yes, heartbreaking, absolutely. But Jason saw them regularly; Jason witnessed children, maybe even friends, being abused (and in some cases, likely killed by said abusers). Jason saw women assaulted, likely saw people trafficked by crime bosses, and honestly I wouldn't say it's too far-fetched to say he probably knew more than just a few people that died from overdose on a regular basis. He never got the sheltered, golden-boy, privileged upbringing that Bruce did.
And that gift of a happy upbringing, or at least not one that socialized him into understanding where the dark in the world really is, lends itself to his failure to understand Jason in any way that matters. Now I don't know Thomas and Martha Wayne that well, and I won't claim to, but they don't strike me as the type of people that would teach their son the difference between a crime of necessity and a crime of desire. Most likely to them, crime was crime, and children will always be a product of their environment until they learn otherwise for themselves. So Bruce started off already with a base level disadvantage to being able to wrap his head around Jason and his gray morality. Like you said, he probably doesn't get that "good people sometimes do bad things to survive."
Circling back to Bruce and his stubbornness, this man carries himself like a steel safe. It takes just the right code in just the right order to get into his head, and even then, it's likely to fail. I think Jason probably got close, especially during UtRH, but Bruce is so stuck in his ways that he just can't program himself to think differently. He can't believe, like you said, that Batman is anything less than the peak, because then that would challenge what he knows about himself and about who Batman really is as a hero. That would break the safe, and then he'd be forced to look at his own actions and evaluate them to ask if he's really been doing the right thing all this time.
Now, in Bruce's defense (flimsy as this argument might end up but I'm sort of thinking out loud), I believe there's this thing in psychology called the Sunk Cost Fallacy, and I think it represents Bruce in this situation rather well. It's where a person is typically more inclined to continue to sink time, effort, and/or money into a project or endeavor they've already invested a great amount of these resources in, regardless of whether or not the cost outweighs the benefits.
Bruce is effectively trapped in this psychological dilemma, where he looks at what he's done and even if it looks like things are getting worse, he can't convince himself to do it differently. He's done it this way for so long and invested so much into it, lost so much to it (i.e Jason and the trust he held for him, almost all of his close relationships, etc) that it would cause an incredibly damaging shift within Bruce himself to admit that he's been wrong. Admitting he was wrong this long and to such a high degree would be catastrophic to Bruce and his ego; it would, at least to me, effectively shatter Bruce's very fragile understanding of how things work.
Jason, however, wouldn't think much of it. Because Jason never walked the tightrope of pretending to be a man among gods. He doesn't have this straight, tunnel vision view that Good goes on the left and Bad goes on the right like Bruce does, and so he's not limited to picking one path in the maze of morality when both options are covered in spikes. Instead, Jason would just go either up and over the whole maze, or he'd just walk around it to get where he needs to go. Jason, at his core, grew up with "when you can't find a clear path, you make your own" in his veins. It's a key skill of learning to survive.
The duality between the two of them, who very much hold each other at arms length while trying to essentially do the same thing in Gotham, is something that will continue to fascinate me. It speaks to the class-difference as much as the difference between their personal psychology, in my opinion, and I don't think that gets played with nearly enough in comics.
