[halixand]

I can't find the source right now but I read somewhere that it would take approximately 100 years to mine the last few bitcoins in the blockchain. The difficulty will be very high and I'm guessing the transaction fees will be high to incentivize miners to keep going. I don't think it's event possible to change the protocol and allow for more coins to be added since this would create an entirely new blockchain?

[SandroG]

For all practical purposes, mining the last remaining coins will be cost prohibitive. High transaction fees might depress the Bitcoin prices. Not sure if anyone will pay hundreds of dollars for a single transaction. I don’t see a sustainable solution behind this.