The most common way why people loses interest on bitcoin investment is when they start to experience losses from the market. Most of them will be discouraged immediately and decide to just sell their coins to cut their losses. Obviously, these are the people who just invest blindly, without studying first how bitcoin works as an investment, and how the market uncertainty affects their investment.
In general, people loses interest from bitcoin when it doesn't meet their real-life expectations. And when being patient does not only mean months or a year, but sometimes 5-10 years of waiting before one can gain a huge amount of profits from bitcoin.
Ignorance is the major reason why people lose interest in Bitcoin. The OP mentioned volatility, FUD and the get-rich-quick mindset as some of the reasons. But anyone who is leaving the Bitcoin space because of these is ignorant. Before buying Bitcoin, investors should have known that the asset is highly volatile, there will always be situations that will cause fear and uncertainty, and Bitcoin is a long-term investment.
People need to build their expectations based on knowledge and not on social media hype. This is why it is paramount to read extensively about an asset or project before investing.
True. The main reason those who lose interest in Bitcoin have a deep knowledge and understanding of Bitcoin, especially during a market downturn as is currently happening. They should be taking advantage of this opportunity to continue accumulating Bitcoin, but instead, they lose interest. Most of those who easily lose interest in Bitcoin do so because they don't see Bitcoin as a long term asset they only focus on Bitcoin when it's rising.
However, those with a deep knowledge and understanding of Bitcoin price fluctuations don't lose interest. In fact, during market times like these they become eager to continue accumulating Bitcoin for the long term. When Bitcoin is in a bull run, they are already prepared from the start, while those who lose interest due to the decline only start buying when the price rises.