The financial sector is roughly 10% of US GDP so 2% isn't automatically a "wasteful" number. It might be, depending on how much more efficient the rest of the financial sector becomes, or how much incremental wealth is created by people using bitcoin.

Also, the issue with 25 BTC/block is entirely temporary. When the block reward gets cut in half in ~2 years your 2% estimate instantly drops to 1% (and then 1/2% at the next reward drop). Of course that ignores transaction fees.