Yeah a 28nm mask set would cost several million dollar.
Bitfountain is on record saying a 65nm maskset would cost $500K at a cheap fab in China. Assuming LC could obtain similar prices, that leaves them almost penny less for the chip development, packaging development, PCBs,  actual wafer runs. miner components, assembly etc.

That money was never intended to fund a 65nm chip or farm, they would have needed to raise more.