Today there are many ICOs that are offering investors an inventory of 100 billion in tokens. However, we have forgotten that the supply of Bitcoin is almost coming to an end and is at a low of 21 million. Miners have mined upto the 17 millionth token and that leaves a remainder of 4 million tokens. The reason for the low supply is because Bitcoin is rare, this also makes it really expensive. In ten minute increments, a new Bitcoin block is formed by BTC miners. Powerful computers keep the Bitcoin transaction information and update them as newer transactions are added. Mining nodes are a must for making sure transactions are legit and verifiable, therefore miners of BTC are in turn rewarded with Bitcoin. Miners are usually given 12.5 Bitcoins with each new block of information. This means that around 1800 Bitcoins are formed daily, but this will not always be so.
I guess we can say that Bitcoin is similar to gold, in which the term mining comes from. For obvious reasons we know that the mining processes are different for gold and Bitcoin. To mine Bitcoin, it is necessary to use computers and processing power to come up with the accurate numbers that make up blocks. As the supply diminishes, the only component that is affected is the pricing and valuation of Bitcoin. Bitcoin can still be used and spent as one pleases, no matter if the demand overtakes the supply.