Bitcoin is the opposite of a pyramid scheme from the point of view of Bitcoin miners. The Bitcoin protocol is designed like a cannibalistic arms race. Every additional miner prompts the protocol to increase the difficulty of mining. From a social point of view, Bitcoin is a pure market. The price of Bitcoins fluctuates based on market supply, demand, and perceived value.
No it is not a pyramid scheme or a ponzi scheme. If it was, it would not have survived for last 8 years. Also, in a ponzi scheme, you are paid to add investors below you, which is not there in case of bitcoins.