How long does registered trademarks/copyrights last when it comes to games?

I don't know if Sim and Tycoon were ever registered as trademarks, or if their owners are currently in a position where their marks could become generic, but generally speaking, companies that lose their trademarks stand to lose a great deal of money. You lose all potential licensing revenue from the mark, for one thing. For another, your competitors are free to peddle inferior products under your old mark, profiting from your hard-won consumer goodwill while simultaneously destroying it. This might not mean much to any of us, since none of us personally owns a particularly valuable game brand, but for a company like Konami or Activision, this has serious consequences.

That's just part of the problem, though. Consider this: a lawyer who doesn't do the things he knows he ought to do to preserve a trademark may be liable for legal malpractice when the trademark becomes invalid. In plain English, this means his client can potentially sue him for every penny that they lost when they lost their trademark. I really can't blame these lawyers for their zealousness.