There are volumes written about CIA exploits and counter-culture movements, as you likely know. And yes...the tsunami of drugs began in earnest in the 80s once America was carpet-bombed with blow. In the 70s, there was tons of weed making to America and even when I graduated HS in the early 80s, people used to sell it in school and it was hard to not find.
Back in the 80s, it was almost impossible to go to any social function and NOT have there be one or multiple people selling coke, and most people were doing it. It was out of control. This was when the floodgates opened up and it has only gotten far worse since then, of course. And here we are, the world awash in drugs with access to countless chemicals being available to anyone who can pay for them.
As for LSD in the 80s? Again, it was everywhere at least in part due to the incredible amount of touring bands (including the Dead, of course) that reached the apex of touring at that time. Here in the Northeast, at least, the touring bands were crushing it in the 80s and I was attending concerts on at least a monthly basis and regularly, a weekly basis. Sometimes seeing the same major band at two different venues in a 2 day span. This was common as in this area we had The Hartford Civic Center, Springfield Civic Center, New Haven Coliseum, Worcester Centrum, and Providence CC in driving distance. This was also a time when you could go see a triple bill of major bands for 20 bucks or less. In fact, one of the first major shows I went to in 1981 was Ozzy Osbourne, Motorhead, and Joe Perry Project and I think the tickets were 10.50 or 11.50, just for context.
But yeah...there was a ton of very high quality LSD pretty much everywhere in the 80s, and at almost any given concert venue you could fairly easily find sheets for 150 bucks or less and could always find paper or microdots routinely. More often than not, it was insanely good quality and getting ripped off by even a stranger was mostly uncommon, but not out of the question. So even selling hits for 3 or 4 bucks a piece back then was common. The real dry spell came in the 90s.