There is NO infinite in this world because everything always change. The technology, the value, the supply and demand keep on changing as the time goes by. In terms of supply, bitcoin is already has a limited supply. In terms of demand, bitcoin adoption keep on increasing that also increase the demand but I don't know how long the demand for bitcoin will remain. In terms of technology, in the future people will create another advance and new technology and I don't know if it is still good for bitcoin. Nobody knows the future of bitcoin but I'm sure that bitcoin will not be infinite as what you think.
I agree, bitcoins weren't designed to be infinite. There is a fixed number of supply, and due to the halving every 4 years it will be hard to chant anything. The problem with infinity is that basically 1 BTC becomes worthless because there will be enough for everybody. The only thing that could be infinite is the universe and this might not even be true.