In your example agile is being undermined by sales partners who are over promising and by project managers who are making excuses and caving in. In other words they are satisfying customers in the short term at the cost of damaging the agency and customer relationships in the medium term. This is a common story. It nearly always leads to unprofitable projects which damage the agencies viability. Many agencies get into serious financial trouble from this approach.

It is definitely possible to do agile much better than this by education clients properly throughout and pushing back on unreasonable sales promises and requests. This leads to solid agency profits on every project.

However this can rapidly unwind with a change of senior leadership.