Engineering-first culture is almost always the wrong idea. It's product-first or nothing. The entire point of agile is prioritization based on business value. Everything always takes longer than estimated regardless of how you manage your project. That's actually a core tenet of agile and one that stakeholders (and budget holders) have the hardest time accepting. Having worked in this industry before agile was prevalent, I can assure you it was never better than this in the past. QA as first-class is a pretty core principle as well. The point of things like Scrum is meant to be visibility and alignment rather than prediction, but impatient people are guaranteed to ruin your life no matter what.
I too have been around before Agile took off, and I too recall how dysfunctional it was before that. I do, however, attribute the positive development to better tooling: Git (and GitHub) instead of SVN/CVS/Nothing, Cloud computing and containerization rather than dusty-server-in-the-corner-with-curmudgeonly-sysadmin, popularity of safer programming languages rather than dominance of C/C++/early-Java, StackOverflow and full ecosystem of answers to every question you might have, etc.
In general, my experience has been that the most wildly successful projects I have worked on tended to involve the least amount of stress, most amount of personal/professional development, and best relationship with peers. The least successful ones tend to be stressful, frustrating, and destructive. The common denominator is that the most successful ones rely on experience, intuition, and professionalism of your staff, the least successful ones submit to tyranny of agile - and when agile isn't delivering success, to double down on it and all those awful "issues".
I'm sure I don't have the wealth of experience you fine people have. But I've been in enough teams and companies to see that whatever methodology is being embraced, it seemed like the X factor was always what kind of people are practicing it. If someone likes always being in meetings, you're going to be in a lot of meetings. If you're on a team with smart people you enjoy working with, with open lines of communication, then the rest just seems to fall into place as long as everyone is doing their job.
Yeah, this is actually my same observation. High-functioning teams were naturally agile even before it was called that. Defining and formalizing agile practices is a way for people who've never experienced it to know what success looks like.
