Scoring System is here: Pretty interesting
https://www.pelotonlegends.com/_files/ugd/f5fb35_1314140e0e184b99a96caf0b2ba0e483.pdf
He also give bonus points for Career Milestones like Winning all Monuments, 150 career wins, 30 GT stage wins, etc.
If you want to view the complete list of the Top 100 cyclists. Here is the link
https://www.pelotonlegends.com/_files/ugd/debc12_0652a828cbe944c99059c64f89917501.pdf
The list is as of 2022 Season.
He has his own scoring system which you can view on the site.
Some active and recently retired cyclists ranking are shown below
10. Valverde
16. Froome
23. Nibali
24. Sagan
25. Zabel
26. Boonen
29. Cavendish
32. Roglic
37. Bettini
38. Cancellara
41. Gilbert
45...
How would you rank them?
They had stellar careers but never reach Iconic Status ala Boonen, Cancellara, Contador, Froome, Valverde, Nibali, Cavendish, Gilbert, Sagan, etc.
Here's mine:
Purito
Kristoff
Degenkolb
Quintana
GVA