It is understood that a hobbyist algorithmic trader will have a difficult time to compete against professional algorithmic traders in finding market ineffectivities to exploit in the general case. However, I would assume those professional algorithmic traders must target higher-value inefficiences (high liquidity, higher volume) to make it worth their time.
For a hobbyist working with much smaller capital and yield requirements, are there opportunities left over for them to exploit, with the assumption that the professional traders have chosen to not pursue them due to the value of the opportunity being too low for them?