Aside from the code getting a license and legal audit, finding a trademark sponsor was important to them too so that someone doesn’t come along and re-commercialize their free and open work under the old brand.

On the flip side, this process is a lot of extra work to do in a very busy and risky time for a buisness. Efforts to open source may fail and I understand when people in charge choose to spend their time prioritizing their employee’s needs first, technology second. I can understand why the open source priority isn’t practical if the company doesn’t plan for this possibility ahead of time.

As long as you are not "distributing" it is absolutely fine to mix GPLv2, Apache License and proprietary code you got from some vendor all together. But as soon as you distribute this, it becomes messy.

And then come all the question on technical integrations, ego ("ugly code!!"), ...