I had no idea Canyon were making bikes 75 years ago. That headset looks very old!
You remember at school when you used to have to make a fake old document for history by soaking some paper in tea....
During my b0ll0cking I was sanguine about most of of my crimes against maintenance but was genuinely surprised that the upper headset bearing had failed so soon. I'd only just had to replace the original headset on my 10 year old litespeed - nowt special, a Cane Creek S3 from memory. Also, the lower integrated bearing on the Canyon was in reasonable nick.
I *think* the premature failure was caused by my toxic acid alien sweat. Most evenings during the winter, I'd chuck whatever bike is closest on to the rollers to spin out the frustrations of the day. My position on the Canyon did tend to drip sweat on to the area around the steerer but I'd wipe around afterwards, specifically to avoid ingress into the bearings. Looks like this wasn't enough.
If I use the Canyon on rollers again I'll rig something up on the sewing machine to cover the danger area. I do have one of those sweat guards but it's a bit short and doesn't work so well on rollers where you need finer steering control. An old pair of Mrs Dr B's knickers might work, and be damn sexy to boot!