The perception that power supply design is trivial dates from the era when power supplies were usually a transformer-rectifier set and a dissipative series or shunt regulator. Because this perception led to inexperienced designers being assigned to the power supply, power supply related problems became severe in the 1970-80 decade. Projects on an 18 month schedule sat on the shipping dock for another 18 months waiting for a working power supply. They are not a trivial design task. The problem and consequences of underestimating the complexity of power supply design and application is relevant to almost all electronic systems, since virtually every electronic system requires a power supply.
Awareness is the first step in solving any problem.
Although somewhat dated, reading this landmark publication should be mandatory for any system or power supply designer and their management. The solution to underestimating the complexity of power supplies is awareness. A short history lesson provides an introduction. Unfortunately, people talk about their successes and not their failures, especially when it is something as embarrassingly simple as a power supply. Hence, the trouble with power supplies was one of the best kept secrets of these decades.