Usually when agile approaches (kanban or scrum) fail it is because there's an unsolvable bottleneck. Typically too small team, lacking knowledge or skill for the scope, problematic environment (development or socially) or someone is pushing "done" work causing skyrocketing development debt that quickly comes to a head - typically a prototype remains in production, switching too early to maintenance mode for business reasons.

Waterfall cannot identify those risks without huge experience. Scrum tends to exacerbate some of them. Kanban with sufficient number of phases tends to expose the problem, but not necessarily fix it.

Strict Scrum is really not the default in tech. "How Big Tech Runs Tech Projects and the Curious Absence of Scrum" is good reading here & matches my experience.

https://newsletter.pragmaticengineer.com/p/project-managemen...

Was it Agile that made this possible, or perhaps the organizational abilities of the companies that made this possible? In other words, if the same organizations used a different methodology do you think the results would be completely different?

I am a firm believer that one, "does not get chicken salad out of chicken shit." Thus, well ran and well organized companies would produce similar quality of products regardless of methodology, and in the same vein, poorly ran and disorganized companies will produce garbage regardless of the methodology.

This, boring things don't tend to be reported on as much.