Yet we have known since Adam Smith that the hidden hand of the marketplace will ensure that the optimal solution is arrived at by letting prices find their own equilibrium. This has been more formalized in more recent times in that the price and quantity of a good will be set at the point where the demand/price curve and the supply/price curve intersect. Further still, dead losses are incurred any time production quotas are enforced. Given this, why do you assert the utility of a production quota on transaction throughput?
The internal market dynamics of a crypto currency protocol is a completely synthetic environment. It's like the internal legers of a corporation. You need management to make decisions in a corporation, "the invisible hand" can not run your corporation for you and for the exact same reasons it can not manage the internal dynamics of a crypto currency. It can punish protocols that chose poorer strategies and reward those that choose better strategies, but it can not chose your strategies for you. In that sense it regulates the internal dynamics of crypto currency protocols but only in that sense.
Why not trust miners to set the tx throughput supply to maximize profit under the demand and supply curves?
Because miners do not have the same set of incentives that users have and the bitcoin exists to serve users not miners, miners too exist to serve users. Admittedly that's just my opinion, but I think most people here can agree with it.