I followed cycling closely at that time and it was odd how guys you never heard of, Indurain & Chiapucci came out of nowhere and suddenly were dominant.
In the 70’s & 80’s doping was mostly steroids and amphetamines which could easily be detected. Guys who popped positive were given time penalties but allowed to keep racing. Then something changed…
Guys like Lemond, Hampsten and Phinney Keifel & Peirce who were winning just a year before couldn’t keep up. Dutch cyclists were mysteriously dying in their sleep of heart attacks. As noted before, nobody’s were suddenly somebodies and the average speeds started increasing tremendously.
Something was definitely going on but it didn’t become public knowledge until several years later. LeMond thought maybe he was having side effects of the lead pellets still in his body. I think he knew guys were doping and was somewhat complicit as he always professed to race clean, from the early 80’s even, but never accused anyone of doping until Armstrong. He made other excuses for his performance instead of accusing others of doping. But think he knew.
I believe Indurain had a nickname of Mr 60 for his red blood cell values. There was no test for EPO early on, it couldn’t be detected but the Anti Doping agency put in a red blood cell max of 50 in the mid 90’s for the safety of the riders. They knew they were doing something to boost red blood cells so set the limit at 50.
I still find it funny nobody thought twice about Francesco Moser’s sudden resurgence in the 80’s while he was in his late 30’s . He was one of the early riders to be trained by Dr Michele Ferrari but the connection to doping didn’t come out to later.