And if there's a fork? As I see it, either you follow the fork supported by the majority of miners, or you run the risk of finding your coins worthless, because everyone else is on the other fork.
>And if there's a fork?
If someone proposes to violate the rules of your blockchain, you ignore them. Only when users support rule changes does the market value them.
>either you follow the fork supported by the majority [...], or you run the risk of finding your coins worthless
Any thing is only worth what others will pay for it. This is the case regardless if you are using a blockchain or not. If the world suddenly decided USD were worthless and you held lots of USD, yes you would find that your USD are now worthless.
The problem seems to me that users and miners have different priorities, and it's the miners who decide what the consensus is, not people who actually hold bitcoin. Of course, miners hold BTC too, and presumably want BTC to hold its value, so they wouldn't, say, intentionally inflate BTC (unlike a government-backed currency). But there's still a disconnect there. Consensus is consensus of miners, not consensus of users.
This is true in the abstract. However in the real world Bitcoin is in such a bind right now. While the USD had been stable in that sense since it came into existence.