I've seen idle speculation here about how much bitcoin would be worth if it achieved mass acceptance - usually assuming everyone would have some bitcoin and calculating that 1 bitcoin today would be worth some insane value equivalent to todays USD.

The only way I could see bitcoin working as a mainstream currency would be as a reserve currency used in international or bank to bank transactions, much like gold would have done a century ago. The protocol in its current form just does not seem to be designed for mass use, but could have many advantages for lower frequency - high value transactions like this. The bitcoin protocol seems to be more of a competitor to SWIFT than to Visa or Paypal.

But while I could imagine a bitcoin-like currency acting as a reserve currency I don't see why the organisations involved would not just start their own blockchain and impose their own restrictions on who can participate in the network. I can see a continued future for todays Bitcoins continuing as an almost unregulated grey market currency, but find it difficult to imagine them going into mainstream use in its current form.

Any other opinions on this? Now that bitcoin has widespread recognition if not yet acceptance is there a vision about how to get from the current experimental model to a stable mainstream medium of exchange?

 edit:  changed the title