Clarification:
Security of a coin will be very tied to its transaction rate × average transaction size, i.e. velocity adoption and wealth of the velocity. The problem I have with the fixed size tail reward as compared to the design I am contemplating is that tail reward only captures those metrics indirectly through exchange price appreciation. I am not sure if the two models are equally powerful. I will need to think more deeply about it. My design also has an orthogonal tail reward.
Edit: some aspects of Monero's tail reward and block size adjustment algorithm are analogous to aspects of my design. There are some other things I didn't mention. I will need to really take the time to distil this into a carefully written white paper. So I would caution readers not to form any concrete conclusions (either for or against any design mentioned here) from these vague discussions.
BTW, I would suggest that Tragedy of the Commons is an ineffective analogy for explaining whatever it is you are trying to explain because obviously-intelligent people such as ArticMine don't understand it. It may be that you are entirely correct, but if you want to communicate effectively you need a differently-worded explanation.
Agreed at the appropriate time. I deem it necessary to be vague since I am months (or moar!) away from implementing my design.