I agree with some of the reasons but not all of them like difficulties in spending you could easily use a bitcoin debit card. These two reason learning curve and poorly understood should be together it looks unnecessary to see them listed as different reasons.Imo cryptocurrencies still needs time before it becomes mainstream.
Crypto hasn't gone mainstream yet simply because most governments don't allow it. Most of your points are valid but not major. These are just some of the difficulties crypto users need to deal with. But when it comes to mainstreaming, these reasons have very little influence (except #4).
This is not true there's more countries that accept Bitcoin than countries that banned Bitcoin.
You are partly correct. But the topic is about crypto going mainstream. You are correct when you said that it is accepted in more countries. But only by the minority. Mainstream means being included or accepted by the group that includes most people. And we are aware that only a very small percentage of a country's population knows and uses Bitcoin. This fact alone implies that Bitcoin or any other cryptocurrency is still far from going mainstream.