fwiw, med/long term strategies are consideribly more difficult than HFT. Also, depending on the product (options, treasuries, etc.) most firms still have traders to manage strategies. For example, the top Options MM firms (CitSec, SIG, Jane Street, IMC, Optiver...) all have traders. Pure play algos is once again, consideribly harder (for certain products).

I still think theres alpha, but I don't think it would be from off the shelf methods that some random youtube trading guru talks about.