Not sure I agree with your analysis on the attendance [for the 10-1 win against Huddersfield], which I will hazard is in the lowest ten in a league game since we got promoted in ‘66.
The attendance against Huddersfield was around the average for that season. With that average of 19,472 being 12th best in the country in a campaign when we finished mid-table in the second tier (we were 30th in the league structure as a whole), I'd argue it was reasonably creditable. You have to see it in the context of the time, where crowds were low across the whole country.
Spurs and Arsenal dropped below 20K several times for individual games in the mid and late 1980s; would they have matched our crowds if they'd slid to mid-table in the division below? We can't know for sure but I suspect not. Everton, as reigning champions, averaged a little under 28K in 1987/8 but drew an average of only 19,343 in the season before Howard Kendall's side really reached its potential. Villa, meanwhile, were in our division that 1987/8 season and won automatic promotion - and their average gate was over 1K per game less than ours. Forest finished third that year in the top flight and reached a Cup semi-final; they averaged 19,670, less than 200 more than we did. In that context, I don't think our crowds that season were actually anything to reproach ourselves for.
Not so after relegation in 1963, on the other hand. The averages of 18K and 14K in 1963/4 and 1964/5 (28th and 33rd in the Football League respectively in the seasons in question), which entailed a fair number of individual four-figure gates, were drastically poor however you try and look at it.
EDIT.
To go back on topic, the standout atmospheres I remember with my first full season attending matches being 1976/7 would be: Bell's comeback, Everton in the '81 Cup QF replay, the Charlton promotion game and the 5-1 derby win.
After it went all-seater it would be: the Wigan play-off, the vital Brum game as we went for promotion in 2000, and the last ever Maine Road derby.
All very predictable, I'm afraid.