More like… source code of the game with rights included for modifying. Even if you release a separate offline version and online DRM verison separately on the PC platform, no one can guarantee that offline version’s codes can’t be used to reverse engineer to replicate an unofficial server or used for exploiting the DRM protected version.
They burnt pretty bad after unending exploits in first two installments of Diablo and after losing rights of DotA. They own the copyrights and they will do whatever they want with it.
Such genre with cumulative progress don’t chime well with offline mode if you want game integrity to be kept with patches and will plan on monetization for a sustainable model also trade between players for a long lifespan cycle.
Not like they gonna make an offline-MMO and not like posting more here will turn their view after being in the industry for so long. No amount of pleas would make them re-consider giving a backdoor to the piracy for the game released on the same platform with DRM willingly. At least not after what they learnt from previous titles.
Console games are kept offline because it’s a torture to modify the game fully because of complex framework and bolster its shortcomings anyway. Any forced online will funnel people to paid online services and your sales will suffer regardless.
All you people had to do was wait for news about old gen consoles; it should follow shortly after the initial release on PC and new gen consoles. They’ll be working with experts and coding initial versions for a later port.
Posting here more for an answer from a high official is in vain. Last word has been said months ago and it was “we will not support offline mode”.