Very interesting link. I am now confused and intrigued that the trademark for "heroin" is listed as being revoked as part of the Treaty of Versailles after WWI.

Though that is not the type of abandonment that IKEA is worried about in this case. In fact it isn't really clear what form of trademark abandonment IKEA would have to be concerned about for this action to be justified. IANAL but IKEA is definitely not worried about the trademark being ruled abandoned due to non-use, procedural issues or naked licensing; they can easily prove the mark(s) are in active use, and the other two are not related to trademark enforcement.

Again, IANAL but we do need to stop spreading FUD about what trademarks entail. Trademarks are meant to protect a brand from being diluted or confused, not to police the world of all parody or reference to some thing. In fact, if the store in the game wasn't even called an IKEA, I am really curious what "trademark" they felt it violated, but unfortunately not curious enough to find out.

P.S.: a better example of a trademark that fell to non-use would be "Twitter". However I personally dunno if there is a trademark that fell specifically because they didn't bully enough people who tried to use their trademark in ways that wouldn't be confused with their brand. That seems to be a made-up invention by corporate lawyers that people just accept at face value. If it really worked this way, the mark "JavaScript" should've fallen a long time ago.