Ryan’s teams weren’t very good for the most part throughout his career.
For the record, Ryan's teams were 2,024-1,960 in his career for an overall winning percentage of 50.80%.
This issue is actually making my point. If Nolan Ryan was an all-time great pitcher on mediocre teams, wouldn't you expect his teams to win far more frequently when he pitched? For his career, his teams were only about 3.5% more likely to win when he pitched than when he didn't. Admittedly, that is skewed by his time with the Mets but even later in his career, he never had the win differential that you'd expect from a great or elite pitcher.
I'm not saying that Nolan Ryan is a bad pitcher. I think that he was a very good pitcher who is HOF-worthy but he was not a great or elite pitcher. Those who classify him there are overrating him IMO. Overrated athletes is what this whole thread was about.