... just silliness...
i don't know about that I believe alot of the functions are just pulled from libraries. most 3rd party software is one of whatever the 5 or 6 file formats are (VST etc) which are standard so it's easy to integrate them into the daw. Most external hardware is of certain industry standards anway (MIDI, whatever else)
I think you are seriously misinformed as to what it takes to develop any sort of DAW or plugin.
True, there are "code libraries" (also known as legacy code) to make certain common functions easier to program.. but as the name 'legacy code' would imply, it's old code generally left over from now archaic programs... that's why the code is out there and publicly available for developers...
Where you are misinformed is in the place that these code libraries take in the programming stage. Maybe, if I was developing a DAW, I could find a piece of legacy code that facilitates VST integration... maybe. But what I couldn't find is how to internally configure that into my particular channel strips or how to enable plug-in chains and bypass or a/b comparison settings, etc...
Yes, there are industry standard protocols like MIDI, OSC, etc... but it's not like these things just exist. Do you even know how many lines of code it would take to make it so that just 1 piece of MIDI CC data could be assignable to a control in my DAW? Do you think that there is some sort of code library that is just magically maintained by developers at large for other people to use? Absolutely not.
EVERY single DAW out there has been 'hand-programmed' using coding methods unique to that particular program. There are literally millions, if not billions of line of code that go into these things. They are painstakingly adjusted and hand-written by individual programmers with only extraordinarily minor elements being drawn from legacy code.
In fact, it's the exact opposite of what you think that is the truth. It's mostly the GUI elements that are taken from legacy code. Things like linking buttons to commands and linking those button positions to the saved graphics are already built into a lot of development platforms....but that doesn't mean that those commands don't have to be written or the graphics created from scratch...
Seriously man, from what I gather, you know virtually nothing about this topic.... You're just shitting on developers with ignorance-based assumptions to justify yourself pirating software.