The patience of the owner was really strong and all the holding he made surely made him millionaire today. Surely, this is the power of holding and this means holding is the way to make rich in the industry. Imagine moving millions of assets only costs small fees, this is why bitcoin will replace payment system big time in the future. Congratulations to the owner, HODL is GOLD it is.
It was 50 Bitcoins so it was probably a miner, and at that time it was way easier to mine, so it's probable that this person had multiple addresses with 50 Bitcoins each.
If that's the case then he could just been using those other addresses over time to fund a great lifestyle. We simply don't know if he just waited or kept using other coins over time.