Bitcoin is permission-less, so by it's design anyone can copy and hardfork it. Anyone can make a "bitcoin dog" or whatever anytime. The question is whether you can rally a community around your hardfork so the coin actually has value, this is much harder to do. I imagine in the future crappy hardforks will be harder and harder to pull off as people start to see they have no real value. Right now there is a tendency for people to see it has free money which gives the new coin some value.