1) Vanguard offers Gold ETFs. Now they would say something ike 'oh that's because gold is used as an actual product ie has a purpose'. But most people accept that gold is also speculative and is the way it is simply because it's been that way for such a long time vs. it's inherent value or purpose. Yes the swings are not as wild and not as easily manipulated (there was the situation with Silver that was years ago) but still it could be done.
2) Stock investing is by and large gambling and whatever income the stock owns in no way really flows measuably to the person who owns stock in the company but seems to drive some type of accepted value going forward. No it's not entirely chance (like traditional gambling) but there are many players and much skill level and 'the regular guy' is not in a position to compete so they must interpret signals and they don't have access to all the signals that a higher level investor does.
3) The entire 'long term' for stock is similar mantra to HODL with crypto.
4) The 'problem' with both crypto and stocks is not really when to buy but when to sell.