It's not even clear it was two years. (No independent evidence whatsoever of its existence prior to late 2013 is available.) If it really were mined for two years with code implemented as was obviously intended by the design (using AES hardware in Intel CPUs), that would be less than 10 PCs mining it, which is somewhat implausible. It is entirely possible they gened the whole blockchain in a much shorter period of time on a server farm or cloud nodes. The whole thing is extremely shady and totally lacking even if the most basic transparency, which is why bytecoin is essentially dead now, and Monero is thriving.