Note I don't work at Xilinx. And be prepared that what I'm about to write may seem incredibly cynical, sorry.
But if I were to take a guess at why the culture is the way it is, I'd say that it's because programmable logic is fundamentally relatively small logic tiles replicated across large areas.
That means across competing companies there's a high chance for infringing upon arsenals of patents for rather mundane things like interconnect, logic families, or memory cell layout where there are only a handful of viable alternatives yet the patent offices were likely duped into accepting multiple legalese interpretations of the same underlying tech. It's a minefield.
Xilinx is not really a chip manufacturing business either. They're fabless. Imagine having a company that designs RAM memory and outsources everything beyond the cell design. If you don't own the foundry itself you're not going to last very long unless you encrypt the memory access protocols, obfuscate your (probably patent infringing) hardware architecture by layers of undocumented tooling, and dominate the industry by buying up any upcoming contenders while cross-licensing stuff to build up a complex ecosystem of interdependent tools required to get even the most basic project done.
On the opposite side of the spectrum, there's Chuck Moore (Forth creator) who in trying to find the simplest combination of software and hardware for his projects devoted a lot of time into a DIY VLSI CAD system. Fascinating history behind it, although the actual OKAD system is essentially trade secret for his company.
But if I were to take a guess at why the culture is the way it is, I'd say that it's because programmable logic is fundamentally relatively small logic tiles replicated across large areas.
That means across competing companies there's a high chance for infringing upon arsenals of patents for rather mundane things like interconnect, logic families, or memory cell layout where there are only a handful of viable alternatives yet the patent offices were likely duped into accepting multiple legalese interpretations of the same underlying tech. It's a minefield.
Xilinx is not really a chip manufacturing business either. They're fabless. Imagine having a company that designs RAM memory and outsources everything beyond the cell design. If you don't own the foundry itself you're not going to last very long unless you encrypt the memory access protocols, obfuscate your (probably patent infringing) hardware architecture by layers of undocumented tooling, and dominate the industry by buying up any upcoming contenders while cross-licensing stuff to build up a complex ecosystem of interdependent tools required to get even the most basic project done.