A few players using them effectively is different than 30-60% of the market being run by algorithms. Granted I can't read much of the article because it is behind a paywall which seems to be very common on HN.
You have to account for the fact that a lot of the algorithmic volume is due to ETF arbitrage. We now have more ETFs than stocks in the US by a wide margin, and each new ETF likely creates another trading opportunity. There are also a lot of factor and smart beta strategies now, which I would classify as more systematic, but these could distort the market more than arb strategies.
Not disagreeing with you, but the arbitrage generally lasts only for a few ms, which makes the article's comment incorrect:
"Visit a trading floor today and you will hear the hum of servers"
In my experience, the machines doing the actual trades are as close as possible to the exchange, generally inside. What's in the trading floor are the client and ML programs that issue the strategies. That said, I've been away from the industry for a few years and it might have changed.
