There you go again cocooned in the top tier. What you fail to mention is many teams in the lower tier at that time were attracting crowds of 3 to 4k. Even teams at the bottom of that tier were getting around a 1000. Now there is not one team in the lowest tier of pro rugby getting 1000 and in the second tier averages are only around 1500.
There was certainly a point in time where lower division crowds where higher than now, 92/93 when fev were in the 8 team 2nd div being an example i can back up to a degree. Whether this was truly representative of general trends i dont know.
On specific crowds that year fev played oldham 4 times in the league and crowds ranged from 3300-4400, games against Hudds were just shy 3000 both home & away. So I guess some teams were capable of drawing, if not averaging, 3-4k.
Whether the above is representative of true long term crowd levels or would indeed constitute 'many clubs' will require stats from more years and a judgement call on what is 'many'.
Incidently, swinton, bramley & rochdale all drew 1500+ crowds for home games with fev, carlisle & london were sub 1k if that assists at all with the 1000+ part of the claim.