Quinn told the Sunderland Echo: "It would be a shame to start downsizing.
"I wouldn't be doing my job if I recommended that we should be paying big sums for players and the people weren't supporting the club."
The crowd for the lunchtime kick-off against Owen Coyle's side was the lowest of the season, 3,000 less than the club's average for the campaign, which stands at 38,342.
Does Niall Quinn have a point?
Under owner Ellis Short, Bruce has purchased Ghana international striker Asamoah Gyan for £13m during the summer, and Darren Bent for £10m the season before.
Those signings have been key factors in the club's rise to sixth in the Premier League table and although crowds hit a high of 41,709 against Manchester United in October, they were still 7,000 short of capacity.
"I thought if we were in the top half of the Premier League, we would be getting crowds well into the 40,000s, but the reality is we are in the mid-30s," Quinn continued.
"The plan was always to improve and while we are doing that on the pitch, off the pitch the lifeblood of the club is just starting to get to a worrying area.
I'm not saying we are perfect, but I always thought I could rely on the support of a massive crowd
Sunderland chairman Niall Quinn
"I am not having a go at people who are economically challenged, but I know there are friends of mine who say it's easier to go to the pub and have a few drinks with their mates and walk home afterwards. But these games are shown illegally.
"I don't want to alarm people but, for me, there are a few question marks.
"I'm not saying we are perfect, but I always thought I could rely on the support of a massive crowd."
Source: BBC Sport
Source: BBC Sport