why didn't hash win out, or for that matter, heroin, or synthetic opiates active in the lower microgram range?
Economics. Cocaine was available in the U.S. for a long time and never had the market share that it had until the 1980s. It wasn't until the cost of marijuana became too high to transport and purchase that the switch to cocaine happened. Hash and heroin were equally expensive. Hash also requires marijuana to produce. At the same time Fat Albert was flying, the DEA was busy spraying marijuana fields, reducing crop yields and driving up the price of hash.
I am no expert, but my sense is that people gravitate towards the cheapest drug that will "do the trick" without getting in the way of a normal life. Alcohol, the official drug of the United States, doesn't do it for all of us. LSD is fairly inexpensive, but it requires a lot more free time than many of us have.