In “Leichte Dellen” iX, a Heise publication, details the situation of software development that requires Agile, but doesn’t allow for it (e.g. due to customer maturity issues). More often than not, Agile is the desired methodology, the team does have the maturity, but the client hasn’t or cannot embark on the methjod, due to contractual or legal constraints or simply missing the resources. Moving into T&M contracts leaves a lot of the realization risks with the client, and requires a high amount of engagement and skin in the game from them.
What to do? Some agile elements can be integrated into the work in order to arrive at the right level of coherence between customers wishes and delivery. And many companies do so.
Heise iX gives a number of really useful links (all of them also in German) to look into. One research paper is especially worth looking into.