My experience is similar to yours, now give the chain a light lub after every ride.
I had to replace the chain at 1700km [not certain if that is considered abnormal], should have replaced chain much earlier as some wear evident on the larger cassette sprockets. Used Wet lub initially but changed to Muc-off dry lub in the summer. Now trying Muc-off C3 Ceramic with the new chain, will see if that makes any difference to chain wear but I doubt it.
One thing I am guilty of is using a chain cleaning device & degreaser occasionally, I was not aware that the chain manufacturers recommend that degreasers / Citric cleaners should not be used on the chain [mentioned in another thread a few weeks ago] Will try just wiping the crap off the chain to see if it helps in improving the chain life.
I wonder if the design on the Haibike idler sprocket may have something to do with the need to lub the chain frequently, in muddy conditions it certainly catches the mud and grinds it into the chain. [not to mention the crap getting thrown onto the rear shock]
About 50% of my mileage is done on forest / wind farm roads, when dry the dust can be very abrasive.
