Scrum, Kanban, SAFe, DAD, etc frameworks are complete in itself. But still many people working in Agile looks customized, fancy, frameworks to help them survive, or as a marketing tool of their services/ offerings.
I personally feel that those who are developing these frameworks have not understood true meaning Agile. Existing Agile frameworks(Scrum, Kanban, SAFe,etc.) itself are lightweight and well structured that any modification/ customization kills agility, and (might) deviate from agile manifesto.
Some of the reasons I could think about for customization could be:
1) Agile is not the culture in the org
2) Leadership teams are missing in Agile journey
3) Instead of embracing the change we try to fit old way of working in new modified way
4) It could be similar to student’s syndrome (My article link)
5) PO and business are not educated enough/ putting extra efforts forming VSM, Forming Value Streams (Project teams/ Feature teams), not forming vertical slicing of user stories, missing on release planning .. etc.
5) XP Practices are ignored in Agile journey
6) Decision making is not decentralized yet and hence guidelines, rules are laid out in different ways by means of frameworks
7) Everyone wants to see their space in framework (save jobs/ not move away from their comfort zones)
If agile Manifesto and principles are well understood, taken at the heart, implemented in true spirit, then we can minimize on such redundant frameworks and work in true Agile way!