So from 1950 to 1960 they were never out of the top 12 in a 30 team league including being league leaders twice, Champions at least once and in the top 4 playoffs another twice.
They then got relegated but bounced right back and were again in the top 10 of a 30 team league for three seasons from 64 to 66 and then the decline started to kick in. To me that would indicate that they were a top team. You have your own agenda and deny this to be so. I beg to differ. They were a top level team by my definition.
Oldham's decline began as early as 1961/62 and came to a head towards the end of that decade.
At then end of the 1967/68 eason Oldham recorded a profit, the first since 1961, of £7,936, in the previous season, 66/67, they had lost £14,000. The turnaround in fortunes wasn't by actually getting more people in to watch them though, they sold several players in order to balance the books.
Oldham were in deep trouble at the start of the 68 season with attendances falling, after a game against Hunslet only drew 2,141 and receipts of £314 the Oldham board held a crisis meeting because the figures were so alarming. They even experimented with a Friday evening game against Warrington but that drew less than 2,000 spectators. Their highest attendance in the first quarter of the 68/69 season was 4,577 but that didn't help Oldham's cash crisis since the game was a Lancashire cup game which meant the receipts were split.
In the 68/69 season they lost £17,000 and had to put club captain Geoff Fletcher up for transfer at £6,000 in a desperate attempt to get in some cash. John Stringer Oldham's secretary said at the time "We don't want to lose Geoff but our financial situation leaves us no choice. We need the money"
and the Chairman Ken Fisher had this to say in October 69 "You can't go on forever drawing £300 and spending £600"
So in the 50's Oldham had a few seasons as a leading light but what followed the seasons in the sun was the onset of a terminal decline.
Other clubs, most notably Bradford had problems in the 60's, however I would hardly put Oldham down as a leading light through the 60's.