Thanks for this post, it seems worth contemplating, if he'd been murdering men for decades, would the 2001 have gone quite differently...
I was thinking about whether he really has done this before 2010, and back when he was a family man/travelling salesman. I just wonder how he would have gotten rid of bodies, before he had access to the Mallory Street property, and this recent trend for enormous, affordable, planters. Nobody had such a thing back in the 1990s or earlier, nor would he have had an excuse to be installing/tending them.
The planters meant he didn't have to dig conspicuous graves in the ground and animals wouldn't try to dig them up. Once he had had the planter in place, he could work quickly, by himself. The owners at Mallory St. were apparently often away at the cottage.
I really wonder if he'd be the type of person to kill, if he didn't have a very careful method of concealing the bodies.