There is a lot of revisionist history or confirmation bias in many folks’ memory of Joe’s record. People forget about the following seasons:
1970 7-3
1975 9-3
1976 7-5
1979 8-4
1983 8-4-1
1984 6-5
1988 5-6
1989 8-3-1
1990 9-3
We had our share of ups and downs under Joe also.
You stopped at 1990, but let's not forget what happened in these years:
2000: 5-7
2001: 5-6
2002: 9-4
2003: 3-9 (and 1-7 B1G)
2004: 4-7
And I think the seniors on the 2000 team were part of the #1 recruiting class in the nation.
Few coaches would have survived past 2001, and nobody other than Paterno would have survived 2003.