The same can be done in science, it just more disclosure of data.
So, yeah, you can look for it with later testing, but all that will do is claw back a winner. It doesn't help anyone that wasn't doing it. Is why none of us have any clue who the best cyclist during the Armstrong era was. With the scary view that the cheating was so widespread that the current winners were still the best if everyone stopped cheating.
The point is to prevent people from doping moving forward because they know they can be caught.
If we had better data on cyclists from when Armstrong was racing, you could absolutely claw back the Awards and give them to the best cyclist that wasn't doping.
Of course, not everybody used EPO and not everybody who did used as much as Riis, Ullrich, Pantani, Virenque, Armstrong, Zabel, Hamburger... Blood doping existed long before EPO. Amphetamines (and strychnine!) were used long before blood doping. Induráin almost certainly used either EPO or blood doping.
EPO and blood doping can still be used (and are likely still used) but noone can push it to the dangerous extremes of the 90's. That will be caught (because such hematocrit values aren't allowed anymore -- and it's easy to test for).
I can't say it is a bad idea to try, mind you. It could very well work. I just have my doubts.
What kinds of steroids and how much of them can I get away with using so I'm in the perfect spot where I am ahead my fellow doping athletes, but still under the bar of detection...