The main cause of dryer fires is lint buildup resulting from poor maintenance, cleaning, or installation, from what I understand. Built up lint is an ideal material for starting a fire. I suppose if you added some sort of sensors, you could make a smart dryer that demands to be cleaned before running if it detects a significant buildup. Might be able to largely mitigate the risk, barring active user circumvention. I'm just spitballing, though.