I guess that SCRUM should have not been adopted as a mainstream/default agile process. I think that SCRUM can work for some teams, but it should be a niche in the world of agile development.

The problem is that people take it as a "best agile practice/process for every team". That is IMHO the biggest issue here.

I wrote an article about my experiences with SCRUM which I named "Why SCRUM doesn't work" :-) You can read it here: https://stribny.name/blog/2018/05/why-scrum-doesnt-work

I'd be interested in any opinions about this.