People heard about Bitcoin from different people with different mindset and expectations. Some bought the types that usually follow during bull run, some are also able to understand that Bitcoin pays in long term. When people with the expectations of quick profits have their hopes shattered when Bitcoin refuses to soar and give them the profits, a lot of them lose interest and only few transition from short term investor to long term investor and holders.
The things that OP listed are also applicable in investments in general, regardless of its nature and platform. Like in stocks, prices are still unpredictable given that the market changes depending on both intrinsic and extrinsic factors in which some factors are outside our control.
Remember that any kind of investment always involve the element of risk. There is still no absolute guarantee that you would be able to earn a profit at the end. This is exactly the reason on why we should rely on gathering our analysis and doing research in order to at least give some safeguards and parameters to check in order to avoid at least losing some money.
Purchasing BTC as an investment should always be treated with extreme care and diligence. If you purchase without doing any research on your part and at the end you would blame the market for your failure on investment, then the bigger problem here would be yourself and not BTC or cryptocurrencies in particular.