Are you sure about this?
I was 4 when Williams was sacked so I know virtually nothing about those times. However, in the 5 seasons before the relegation season of 1982, our two highest finishes were 9th and 15th, having also finished 18th, 19th twice and then 20th to suffer relegation.
In fact, since the 3rd placed finish in 1971 until 1982 we finished in the top half of Division 2 only once more, suffered one relegation in 1975 and finished 17th or lower in Division 2 on 8 occasions. On the face of the stats alone they don't appear to show much promise, so I'm interested to learn more about the club at the time.
Just by way of comparison, between 2006 and 2021 we managed 13 top half finishes in the Championship in 14 seasons. We've never had it so good in this division. In fact, I think 4 bottom half finishes in the last 18 Championship seasons is pretty good going.