I don't know for sure why crashplan ceased but I recall reading here on HN that someone happily posted they were using like 16+ PB's on Amazon drive which is insane, I'm sure plenty more abused it but in reality that much space is quite a few average users I'm sure. Crashplan could have created some sort tiered pricing structure for those using over 5-10 TB possibly but to build up your service and brand and dump it suddenly is really un-trusting.

I wouldn't be surprised they just ran out of data center capacity and decided cutting loose low revenue consumers was cheaper than building out new space.