Relaxed beyond adjustment from non-use.
I would say you were sold a dud and the seller knew.
Probably. I paid $60 for it last year on eBay, and while the description was technically accurate it hardly reflects what I received. "MINT PROTO 6062A TORQUE WRENCH.1/4" CALIBRATED,ALL PAPERS, 40-200 IN LBS +METRIC". Calibration certificate was from the 90s, and the wrench off by 50% or more across most of the range.
If what you say is true/accurate, there's no reason to expect any clicker wrench to last any more than a year or two under regular use.
I bought a Craftsman clicker in the late 80's. It was used semi-regularly for several years before the usage went up to just about every working day. Luckily, I worked in places that had access to calibration equipment. It never once needed adjusting and was more accurate than the Snappy I bought later. The only reason it went away (after nearly 20 years) was because the plastic handle disintegrated. The Snappy is still with me and it's nearly 20 years old now.
I've got plenty of old torque wrenches that have served me well over the years too. This is the only one I have ever had issues with.
I can't say why this one had issues whereas none of my others have. Like you, I too *suspect* someone sold me a dud knowing full well what it was.
Tools can certainly be cared for to last a long time. I'm not suggesting torque wrenches melt with age. The question on the table was 'would you buy a NOS 1/4" torque wrench on eBay?'
I might, but only from someone with a positive history of selling that type of item specifically OR a *current* calibration certificate.