Does it really cost $30 to mine one testnet bitcoin?

If the basic formula is:

Code:

time = difficulty * 2**32 / hashrate

And the current difficulty on testnet is: 53696268

Assuming it costs approximately $12 to rent 100 TH/s of SHA256 for a day we can use the calculator code by Phelix (https://bitcointalk.org/index.php?topic=5826.0) to arrive at 0.444 tBTC per day with 100 TH/s of rented SHA256 hashpower.

Code:

$difficulty = 53696268;
$hashRate = 100000000000000; //100 ths
$hashTime = ((float) $difficulty) * (pow(2.0, 32) / ($hashRate));
$blocksPerDay = (24.0 * 3600.0) / $hashTime ;

echo "blocks per day: ".$blocksPerDay;
//blocks per day 37.46 @ 0.012 tbtc per block
//0.444 tBTC per day

Unless I'm making a mistake somewhere this means it would take more than 2 days to mine a single testnet bitcoin, and put the mining cost for one tBTC close to $30 USD...

Is this the reason most testnet faucets have disappeared and some people are asking to buy testnet coins?