Actually for DC-DC converters, programmable digital controllers (like MCUs, DSPs, FPGAs, etc) are still uncommon in most applications. You'll find them more often in DC-AC converters (VFDs, GTIs, etc), since generating a sine wave is trickier in analog than generating DC. For DC-DC, you'll probably only find MCUs in high end, high power converters. For simple applications you're likely to find a specialized analog controller IC which performs all the desired features, at lower cost and complexity.
However, recently there has been a trend in controllers to integrating more digital functions, and lots of "programmable controllers" are starting to emerge. They offer a lot of the flexibility of a fully programmable solution, but with less complexity (no ADCs or DACs or digital filters to program).