It is possible (and likely) that enough bitcoins will be mined to make mining for the block reward unprofitable. I believe that the result is that mining will stop completely if there are no transaction fees.
If any miners stop mining under the current system, then the remaining miners become more profitable. That feedback doesn't exist in your system.
This in a deflationary system there is a positive feedback loop as the remaining miners become more profitable causing a stabilization of the hash.
That sort of feedback does not exist in the inflationary loop.
If you are mining gold, your result is proportional with the work you deliver. No matter what other miners around the world do. The same for my mechanism. It can be compared to mining gold. Bitcoin mining cannot.