The recruiting work of Jehovah's Witnesses has never been very effective. Such low positive results for such great efforts. But the members are paying the gas money and expending the hours, so Watchtower is not really losing out.
Don't forget the loss of revenue in the lives of each and every JW...year after year after year. Time preparing for going to meetings...time wasted while at the meetings...time preparing for field service...time wasted while in field service...time wasted and money spent going to and from circuit assemblies & regional conventions...time wasted working on Kingdom Hall building projects...time wasted in the Bethel lifestyle...etc...etc...etc.
In reality the average JW may be spending 75 to 100 of unproductive hours and more each and every month as a Jehovah's Witness...that's nearly 1,200 hours yearly of what could otherwise be tme spent earning revenue/income. Last I heard minimum wage in the U.S.A. was going up to $15 an hour...1,200 hrs X $15/hrs = $18,000 of lost annual revenue/income for those who make minimum wage alone...$18,000 of lost revenue/income year after year after year adds up...in ten years that's $180,000...in 20 years that's $360,000. Any wonder why many if not most senior retiring Jehovah's Witnesses are not prepared for old age!