If you don't trust a coin to operate according to your expectations (e.g. a 21M limit), you can verify the source code and/or run a node yourself. This way you

If you don't trust a coin to operate according to your expectations (e.g. a 21M limit), you can verify the source code and/or run a node yourself. This way you can yourself guarantee that all transactions happening on the network (that your node is part of) operate according to rules that you agree with. There are already multiple forks of Bitcoin, yet it doesn't seem to change market's perception and valuation of the original Bitcoin.