A few thoughts.
1) It's kind of sad to me because Lowes and Jimmie Johnson are just synonymous, kind of like this era's STP and Petty. It's just a shame they couldn't have found a way to be involved at some level with the team until Jimmie retired, like Axalta did with Jeff Gordon. Though technically not the same company, Jeff got to retire with the sponsor he broke into Cup with.
2) Even though technically NASCAR didn't lose anything, there is no good way to spin this as far as NASCAR is concerned. If you're trying to convince some company to sponsor YOUR team, there is no good way to spin this.
3) If Lowes indeed is not getting the ROI they are looking for I would say a good portion of the blame is on Lowes themselves. When was the last time they did ANYTHING with the sport other than put a car on the track? The haven't done a new commercial featuring Jimmie for a LONG time, and in their stores around here, you basically wouldn't even know they were in the sport. One of the three local stores has a banner of the car on the wall that is a good 10 years old and nothing else. The other two stores don't even have THAT. At least around here, the ONLY Lowes/Jimmie Johnson item you could EVER buy in the store, even back in the "Glory days" was a freakin' gift card with the car or the number on it. If you want to get return on a NASCAR investment, you have to do a hell of a lot more than stick a logo on the side of the car, especially in the current climate.
4) The whole thing probably IS my fault, because despite my love for the 48 team, I buy 99% of my stuff at Menards. In my opinion, Menards make Lowes and Home Depot look like rank amateurs.