In as much as Bitcoin is a very nice investment and has proven itself for some years doesn't mean that anyone who has the awareness of it should invest I mean everyone has choice of investment and there are other investment that are very nice and promising.
Below are the reasons why I think some people don't want to invest in Bitcoin.
1. Lack of understanding: there are people who still see Bitcoin as scam till today reason because they mistake trading ( loss and gain) to Bitcoin investment.
2. Lack of fund: these are people who understands how Bitcoin investment works but because they don't have good source of income that can help them sail through...
3. Lack of interest: there are people who has the fund I mean a good source of income but they are not interested in Bitcoin investment.
I would argue that there are some assets everyone should at least own something of. The difference between real estate and bitcoin is that the latter has more use cases, can be turned into cash much quicker if for some reason needed and the best part is that you can own it in small fractions.
If someone tells you that owning a house is as important, then firstly I don't know whether that is true, and secondly you usually can't own fractions.
Bitcoin is very different in that regard because why not just own a million satoshis? Or 100,000 satoshis if you can't afford more? It is also very different because the housing market is mature so to say. It would be nice to own a house because it saves you rent, but this is by no means always the optimal solution. Look what's happening in China, they built too many houses and are now in huge trouble. Yes, too many houses! I know there are a lot of countries where there is not enough housing and therefore rents explode, but in China the rent is about 25% or that in the USA.
The chance that your house makes you 100% gain in the next five years is much lower than bitcoin making you 100%. And a house often times ties up all your resources.
As I said you can own bitcoin in fractions and you are all set. Many people think they need a whole BTC, but there is no need for it and isn't possible either as there is only 21 million, meaning that only 0.25% of the world's population could own a whole BTC. Just do the math and think about how many people already own a good bunch of BTC. If bitcoin keeps expanding throughout the future, some folks might be very happy about owning 1/10th of a BTC.