This is a subject with many variables, but I'll take another swing. First, I am not associated with an aggregator but have had close relationships with them for over 11 years. I wrongfully described the meeting. The gentleman was a co-founder of one of the aggregators who had moved on and was doing consulting. I believe it was this individual that coined the phrase "history of object" and it's always stuck with me. Our discussion was about a brand with over 1,000 locations losing much of their organic traffic because a zealous agency account manager had set up a keyword-specific domain with toll-free tracking numbers and then hired a service with the ability to suppress listings to hijack much of the organic traffic. The campaign was canceled within days, but the damage & confusion to the local ecosystem was enormous. The cleanup took months, and if it wasn't for the aggregators pushing fresh data, it could have been much longer. The point is that the ecosystem responded to the fresher data to correct itself.
I brought up GMB specifically, but I should have said the local ecosystem more generally. It does respond to dates. Joshua, I applaud you for logging into your client accounts monthly. We don't know for sure if it's a factor, but think of Google's own search where you have the ability to click on Tools and select results found within the last week. Stale is stale. Renewing with the aggregators for $40 to $50 makes sense to me.