On a technical point, even if the company has ceased to exist, its assets might have been sold, or it might have assigned its copyrights at some point, or perhaps a third party has a copyright interest, and there would be no way for me to know about that.
The broader point to make is that this is a general policy of mine – I deidentify all software that I discuss in any of my RE writeups. Having a blanket policy avoids needing to make ultimately arbitrary decisions about what to name and what not to name – and in any case, not naming the software doesn't prevent anyone from reading the writeup and taking inspiration from it if they choose.