Modern Portfolio Theory> is not a book, or a meme... It is taught at respectable universities.. It has limitations (and assumptions), of course... but someone who applies those principles will out perform (on average) someone who doesn't ceteris parabus (otherwise with the same initial conditions)... excepting maybe someone armed with an even better model of reality, and therefore wouldn't apply it.
Pretty much horse gambling theory applies to the stock markets and bitcoin arbiters too...
You can successfully do these things by applying the correct principles.
The fact that you have something better to do, or can afford to do, or can't afford to do, does not apply... If you make better returns doing something else, you should be doing something else.
> What I read you saying above here is that if the market is improving, the swings are getting dampened, but what I see in the historical record (no guarantee of future returns) is that, compared to the period from 1930 to 1970, the more modern "high speed trading" market has sucked balls.
Actually... I think maybe the price wanders within it's natural variance now... In the past, the prices may have been more stable... artificially... because people just kind of stuck with a price more... fewer of them, getting better returns on less liquidity.