Soon, I will be putting on a new roof, and installing a new ridge vent.
Several highly-regarded roofers advised me to either scrap my fan, or
the ridge vent. I have a ridge system now, and it seems to do a decent
job. The power ventilator, mounted near the ridge vent, has not worked
for about 15 years. Like you, I was told that the fan probably drew
most of its air from the ridge, rather than the soffits.

Based upon expert advice, and my experience, I am having the fan
removed and it's hole covered. I will be installing a few more soffit
vents.
Tom