Becoin: the 21 mil. cap is a different issue because Bitcoin was set up from the very start to divorce the issuance rate from resources expended by anyone. However much miners may toil, they can not significantly affect the amount of BTC issued during any given timeframe, and that's how it was from day one. (you know the caveats that apply, I'm sure.)

I put it to you that what the miners produce isn't BTC, it's the processing of transactions. I think you'll find my assertion is backed up by pretty much everything going back to the original whitepaper.

To reiterate: While changing the issuance cap is possible, everything down to the difficulty balancing shows the cap is a fundamentally hardcoded feature of BTC that isn't meant to be subject to market forces, and this is known by all participants in the economy. A cap on TX rates, instead, is a new development and a direct attempt to control the miners business practices.