some lame eater egg addd by a different company
Wow... just... wow. You couldn't be more wrong if you tried. Cyan and Broderbund directly added the easter egg, it's not from another company. The easter egg even showcases Cyan workers.
There's nothing lame about it for those that grew up with this game and series. That's extremely callous and dismissive.
The developer console that ScummVM breaks disables a lot of other useful features as well, as you can view on the page for Riven on the cutting room floor.
My understanding from ScummVM's website is that ScummVM has to be modified to work with each specific game. As such, ScummVM doesn't break or disable anything in a game they try to support, it just doesn't support everything in whatever game they are working on as of yet.
So, it's a matter of someone figuring out how to get various parts of the game to function with what ScummVM provides, or write something new for ScummVM to handle it. But that's just my impression, I don't work on it.