I personally don't feel its because of many of the reasons listed above, except for being "new". Even then, I don't think people are concerned about the longevity of the currency, as its been around much longer than most people invest in. Instead, I believe its the lack of documentation, and usability that scares people away. Unfortunately, for Bitcoin to exist in the way it does, it had to step out of the comfort zone of many people, and introduce new concepts. Now, its known that the majority of people aren't particularly fond of change, which Bitcoin does a lot. Traditional currencies have always been pretty much the same, and the principles are taught at school from a young age.
Bitcoin doesn't have this luxury, and currently we are stuck between unnecessary complexity, and jargon. Even when you come to this forum, many experienced users who have great knowledge in the subject aren't particularly good at communicating in laymen terms. Of course, Bitcoin requires someone to be specific in order to be clear, and concise about what you're talking about, but this is not friendly those that are just adopting it. I'm guilty of using jargon, not because I'm trying to sound like a smart arse, but that's how it rolls off the tongue, and is specific to what I need to communicate when asked a question about Bitcoin. However, that's just going to confuse, and scare someone new away. Unfortunately, the documentation which exists online isn't that great in communicating in laymen terms either. This is not only stunting Bitcoin's growth, but its hurting the chance for someone to come back later, and be willing to learn.
The challenge that we have as a community is trying to make it accessible for anyone to adopt Bitcoin in a quick, but secure fashion while also introducing new concepts. For example, a paper wallet is actually quite complex to a new user, because they aren't used to the practice. Unfortunately, the very name "paper wallet" although seemingly self explanatory is something hard to grasp for a new user. A "seed" is also something alien to them. These are just some of the very basic issues that we have to find a solution for to make it easier to adopt. I know, the general consensus is that a willing learner can get through this, and understand. However, if we truly want mass adoption then we should be making Bitcoin as easy to use as possible.
Good points Welsh.
While we generally discredit custodial type Bitcoin instruments like Paypal and Revolut
they are actually making Bitcoin 'ownership' easy for people who otherwise are
not interested in buying hardware wallets, creating and recording seeds.
Also the same goes for preloaded smartphone wallets so people have a hassle free
instrument on their new phone ready for them to explore Bitcoin ownership.
These all make it easy for people to get involved without the scary hands on approach
we are accustomed to.