Recent reliability has been a factor for some, they seem to have deteriorated in that respect. The biggest factor for most users and probably the trade is the battery prices.
The top end 36 volt 9.6 Ah battery for example I last saw at £1050, a truly shocking price for that capacity. I don't know about KTM, but Trek tried to get round that with a choice of much smaller capacity batteries, but obviously that wouldn't suit many and the prices were still much to high.
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