There's a cottage industry forming around finding market distortions caused by bad algos. You'd think that there wouldn't be a bunch of bots running around making stupid decisions, but there are a lot of bots that haven't been updated in some time and were put in place according to some idealized rule-based model in some esoteric area of finance that one guy came up with.
It's kind of like asking yourself seriously how many computers out there are running outdated software. The less fundamentals matter, the more computers handle various activities that have a more or less direct impact on prices of marketable securities, the more this is a valid strategy. It's basically anomaly detection on very messy data.
If transaction costs keep coming down and data becomes cheaper (both of which seem likely), trading as an independent might become less ludicrous than it is. And to be clear, it is currently ludicrous. Transaction costs will eat up any potential gains on the retail side unless you're operating with very large amounts of money.