Although the OP asked an interesting question, it is also very interesting to me that during the first 4 years as much as 50% of all Bitcoins were mined, and of that as much as 2.625 million in the first year.

Therefore, we can conclude that the first users were really privileged in some way, because not only could they mine with their personal computers, but they also had the opportunity to mine blocks with the highest rewards. It was, without any doubt, perhaps the most interesting time in the short history of Bitcoin, and the most fruitful period in someone's life if by any chance he saved the mined BTC for the future.