Of course, if you take my idea and use it to make money then my business will suffer and I will have less incentive to have ideas in the future. We need a period of protection for ideas to ensure that creators keep coming up with them because they are vital to our culture. It is, more than anything, part of what makes use human. But for exactly that reason protection periods should also be kept as short as possible. Once that period has expired, others should be free to reuse, rethink and remix those concepts and incorporate them into their own ideas.
Copyright laws are of less benefit to creators than to corporations who market their work, giving them a meager share of the profit. If Disney no longer had a lock on material that should be public domain by now, maybe they'd have to employ more creators. And maybe someone else would make a decent Mickey Mouse cartoon -- which I don't think they've done since the 1940s.