If no technical analysis was possible, then they wouldn't be able to run bots on markets, or easily trade at all. Some technical analysis is highly effective, usually when combined with other analysis, and used by a seasoned trader. Human behavior can't be boiled down to any simple algorithm though. I won't rule out it being possible to predict the market mathematically though.
Does that even matter anymore though? A high volume of trading these days is done by bots. If the bots trade on technical analysis, then you can use technical analysis to trade with or against them.
Without technical analysis to at least some degree, trading would be gambling. Traders couldn't consistently make as much as they do if it was gambling. Sure, the simple analysis we do isn't 100% correct, but I'd be worried if it was. Of course, if it was so accurate, it very quickly wouldn't be any longer as more and more used the system, and others figured out ways to game them for money.
HFT's are great are keeping trends, but they still rely on fundamental traders to create them. They are a way for traders to make profits while away from the screen. I don't think they are a replacement for human trading though. Especially how little these machines are given to play with compared to the overall capital of the firms that use them.
Fundamental analysis is honestly my favorite form of analysis because I understand economics. It's just like technical analysis that uses if-then statements, but instead of technical charts it uses economic surveys. Despite having the switch from Janet Yellen to Jerome Powell little actually changes in the interpretation of the Federal Reserve statements. Inflation is still inflation. Interest Rates are still Interest Rates.
Not all the bots are HFT's. Especially not in the original sense. They're getting surprisingly advanced. They're not quite yet replacements for humans though, no. Humans still make far more, as far as I'm aware. But they can also lose far more.