1/ Agreed. No one's going to share all, or an essential component, of a strategy printing money live. I'd go a step further: even if someone described some high level strategy in words only, it's still nontrivial to build it out. Devil is in the details.
2/ However, quant/HFT trading is building a cathedral, not a wall. Overused metaphor but it's so apt. The foundations are still "alpha" to newcomers. For example knowing how to normalize data isn't going to print you money, but without it you definitely won't.
3/ In fact, the most important alpha is the research process. Any specific effect will decay, as @quant_arb mentioned. Learn to play the game though, and you'll adapt. Principles and intuition over tricks (but doesn't mean I won't share a clever trick here or there)
@chameleon_jeff By the time it reaches Twitter it’s just all PvP.