yes having no internet will be why the crash happens... a work around would be making a Paradox account * then Galaxy - Stellaris saves your log info as a note file and you play off line

to be clear
* Paradox accounts are free, you can have more than one [I have 4] and they know what you tell them. If you want to play Paradox builds to get access to older content then you must link your Gog key to the Paradox account and yes at that point it is very much Drm but you don't need to link account to only play your Gog game

I just tried loading Stellaris without an internet connections. It looks like it only does a phone home if you use the launcher. You can launch stellaris using stellaris.exe in the game folder and it will not check for an internet connection.

I checked as well, I even shut down my Internet connection during the instalation process (I used the offline installers). Using stellaris.exe launches the game without problems.

@ConsulCaesar does the offline install not have the launcher or you just didn't use it?
for others;
its also possible people with 32 bit Window systems will have issues with the new launcher settings because their network files arn't upto date i.e, being on or off the internet wouldn't matter because the Net files just arn't installed

There are some files labelled "launcher installer" in the Stellaris folder as well as dowser.exe which should be the launcher itself (right now it shows an error message if I try to open it).

But stellaris.exe ignores all of that.