I would say even much LESS than 1 billion hours!
There's a saying that; "even a blind squirrel finds an acorn once in a while." So if 8 million jw's are spending even 1 billion hours per year in fs, the number of converts per year should be much larger! Field service has become a formalistic regiment and nothing more.
My wife is part of a group of 4 sisters that always work together twice a week. They drive around to laundromats, bus stops, and coffee shops. They have bible studies with old women and troubled single moms. It's nothing more than a social circle that meets twice a week.
just saying!