I would program a modest uC with an ISP programmer, add a sleep mode and change the RFID reader and servo by a simple relay or transistor to open the lock. This would use an insignificant fraction of the power their system is using.
I would say they've also used an expensive audio amplifier to amplify the signals from the piezos into something the Arduino can read, I would have designed a simple circuit with 4 OP amps or just 1 op amp that could send an specific signal for each piezo for the uC to interpret.
Only the arduino mega costs around $40, with all what they've used I would say it would cost quite a lot more.
With discrete components and a uC chip it would've been less than $10, assuming the electric lock was already installed.
I guess that program has been used to show the system in operation, otherwise it is redundant.
They're not making anything, they're putting things together.