When it's all said and done, he likely finishes top 20 all time for rushing yards. Of all time players there, only 4 are not in the hall of fame. Three of them will be: Frank Gore, AP, and Steven Jackson. Among the top 20 rushers of all time, only 2 have better ypc.
Ummmmm, not a really good argument though? One of the most efficient and productive RBs of all time. That's a pretty good argument.
If 29 year old shady plays for 3 more years, he doesn't even need to have great seasons (around 800-900 yards a year) to pass Thurman's and OJs rushing yards mark and could possibly vault him into the top ten.
I'm all for a discussion, but I don't think both sides have a good argument here, you are siting running backs with less than 5,000 career rushing yards in 8-9 years of playing, maybe you need to use a better reference: did you just Google "RBs similar to LeSean McCoy" and post every name that came up to try and look like you know what your talking about?