More fans doesn't equal better cooling, after a certain point, it becomes a matter of diminishing returns.
A tiny case is under 20 Litres. A mid tower is generally around 45-50 Litres. A Full tower is @ 70 Litres and a Super Tower is @ 80+ Litres of internal air volume.
Now take your average 120mm fan pair. That'll move @ 50 cfm. So in a tiny case, you'd replace the entire air volume in little less than 10 seconds. In a Super Tower, it's closer to 4 minutes. So you'd be looking at @ 20x 120mm fans in a Super to even approach the amount of flow possible from just 2 fans in a tiny case. Or @ 10 fans in a mid tower.
So more fans isn't necessarily better, it mostly depends on exactly what fans you have, what they are doing, what they aren't doing, and what can reinforce their performance vs detriments.