CSound is a grab-bag of mediocre DSP algos hacked together from various sources by academics who have no interest in professional production values.

While you can build your own synths with Csound, they don't usually sound very good.

Games are actually more likely to use PDLib, although there's also a lot of custom C++ in some games.

There's a significant difference in sophistication between the crude algos in Csound and the algos in successful commercial VSTs like Serum, Uhe's synths, the Roland Cloud collection, SoftTube, UAD, and FabFilter mixing tools, and so on.

I don't know about "crude," but yeah. And honestly? There is no comparison between the components in Max/Pd/sc/ChuCK and any of this stuff either (I joke with my art-music friends that I like everything about Max except the sound ;). You'll never hear something like Cytomic's The Drop (a filter that can crush your CPU) or serious tape saturation, or sophisticated EQ curves with lots of warmth and character.

It's true that you could create any kind of filter, oscillator, DSP-whatever you want with these systems, but in practice, the people working with these tools are not U-he-level DSP programmers, and it shows.

I wish that weren't true, because I'd much rather code stuff csound-style than work in a DAW with a bunch of expensive plugins.

But is it true that you can run VSTs in csound? Could you use commercial VSTs, but write fancy controllers in csound?