This is the conundrum of creating a better marketplace. An optimal market has 0 profit opportunities. In order to make money the market must be flawed in some way. Luckily in the real world perfect markets don't exist, but in certain sectors technology has made life difficult for people who had previously had a solid reliable income with the old inefficient system.
That doesn't quite right to me. A market with the smallest profit opportunity of a selection (say worse that government bonds) wouldn't see investment to correct that inefficiency. Zero may be 'best' case, practically speaking though no one's going to arbitrage an opportunity, that's less than the opportunity cost.
So it seems to me the optimal market would a profit opportunity somewhere between being the 2nd best profit opportunity and zero profit opportunity, depending what you set the opportunity cost at.
In a perfect market the profit opportunity asymptotically approaches 0.
But a perfect market is a mathematical model, not something that you would see in real life. As you note some entrant is not going to jump into a market and undercut the competition by 1 cent (from 2 cents) and immediately capture all of the market share.
But this does illustrate the dangers of making a more efficient marketplace if your goal is to make profit.
That's rediculous. If a market with 0 profit opportunities exists them time is frozen and all future innovation is impossible. It means that every possible inefficiency of every single person working has been removed. Humans are never perfect beings, and usually far from it, so there is always opportunity for more efficiency. Also the goalpoint is constantly moving as more technology is created to replace older ideas.
If we ever reach a so called "optimal market" as you describe it then GDP growth will also stop, as will personal income growth and all manner of things..
