But while transaction processing costs money to perform, it does not seem to be incentivized properly. While there are concrete rewards for generating currency, there is no corresponding concrete and immediate reward for processing the transaction, and voting in transaction approvals. This might be a real obstacle in general acceptance, and some of the root cause behind all of the "so where can I use this" kind of questions we hear all the time.
You seem to equate mining = generating bitcoins when that isn't true. Mining = hashing transactions into irreversable* blocks is part of transaction processing.
I do agree that the other parts seem to be neglected.
The entire processing chain involves
1) Validating & relaying transactions
2) Hashing transactions into blocks
3) Validating & relaying blocks.
Currently only step #2 is compensated but it IS part of transaction processing.
* well technically very difficult to reverse