With the moden approach of development that leverage a lot of complexities to some development ecosystems like Drupal, the organizations need to optimize a lot the time and resources giving a prompt answer to the clients expectations about complex functionality that more than ever is dispersed in a lot of applications that are taked as a reference for many product managers. How to say not to a feature request that is contained in a module ready to download and install? Drupal works in easy way and have thousands of features ready to use and the client expecations raise for the people that every day is living internet and modern web applications which provide very interesting tools that make the life easy for the web users.
To react in agile manner the Drupal service companies need a high level of organization and expertise to prepare good project planning and budget estimations to doesn't lost profit while try to satisfy all the complex request from the product managers from clients. The reason for this phenomenon is easy: Drupal is agile if you ara capable to understand all the available APIS that are provided from Drupal core and from most popular (and non popular but needed) contrib modules and have that capacity takes a lot of time of investigation, experimentation and a big learning curve. The truth is that only the service companies that are supported by experimented Drupal team are able to get sucessful projects that satisfy the most exigent clients in a very short and aggresive deadlines.