Because, without AI, the approaches taken would be illegal. Large companies are now being affected so there is money invested in protecting their trade secrets.

Can an LLM be "clean room"? Are weights trained on decompiled code considered "tainted"?

Where is it illegal? I know of many examples where people are running companies doing this across a variety of domains. (not software, no ai)

Trade secrets have no legal protection

It's a fair question. Are you familiar with clean room concepts and why they are required to circumvent the legal hurdles associated with reverse engineering projects?

Where are you getting this legal hurdle stuff from? People have been doing this since forever

Sandy Monroe is a great current example, tears down cars and builds reports. The auto industry has distillation built in