The #1 obstacles to implementing agile are clueless, recalcitrant managers. I once worked on a team where we did KANBAN. The way we did it was waterfall.
I spoke up at a meeting to my manager. I said we do waterfall, he cut me off, shut me down and said in his heavy Indian accent NO WE DO KANBAN AGILE! I said "right, we do all the requirements, then all the development, then all the testing, and then get mad at the BA when we find defects and gaps. Agile!"
If you can't tell, we didn't get along.
Now, five years later, that guy is a very successful director, and still at Fiserv. When directors of software development think that requirements->development->testing->panic->finger pointing is Agile, you begin to see the problem.
Fiserv will never be Agile.