Bitcoin mining is a process that requires ASIC miners, which can be very costly. Initial setup for an ASIC miner could run into the thousands and the cost of electricity could be hundreds or even thousands each month. ASIC machines ASIC machines are usually placed in large, specialized mine farms which can maximize efficiency in energy use and take advantage the cooling system to reduce costs.
For miners who are primarily individuals with smaller systems investing in ASICs is not affordable. Many novices think they are Bitcoin will be the highest-profit cryptocurrency to mine, without knowing the reality of competition in the market.