When they explain to me how ISRU (in-situ resource utilization) can fabricate a replacement for a blown microchip or a refrigerator's compressor - based only on the equipment you can bring to Mars in a couple of space capsules - I'll be ready to begin seeing Mars One as something other than an insane pipe dream.

This article nails it: these people would be living an 18th-century lifestyle. But it would be one utterly dependent on 21st-century technology for something as basic as breathable air. If their 18th-century lifestyle can't keep their 21st-century technology working, and the organizing company can't drum up enough money to send regular resupply flights for decades to come, they die. Simple as that.