What exactly happens in 2100 when AutoCAD 2005 goes "public domain" but the company does not need to provide the source code, there is no licensing server avail

What exactly happens in 2100 when AutoCAD 2005 goes "public domain" but the company does not need to provide the source code, there is no licensing server available, dongle support, whatnot. Also the company still retains the AutoCAD trademark so you cannot legally distribute modified copies of 2005 if they still contain AutoCAD/Autodesk branding in them. That's for 2005. For today's software that depend on connectivity, nobody gets anything if the clients are pushed to public domain. You still lack the entire infrastructure. The server code is not a product, its a service implemented by the proprietor, that's beyond this law.