The important thing to note is that the node count and network utilization has not grown very much for sia.
The value of the coin has grown, but that doesn't really affect the network much. (Trading has increased price not demand)
The host only lowers the price so its the same fiat price.
Renters think in fiat, it has to remain cheap or they will probably use a more easy cloud storage alternative.
http://siapulse.com/page/network