1. Hold Mentality.
2. Using Web wallets or using Exchange as wallet.(not using own wallet)
3. Block Confirmation time
4. Most of government do not recognize it.
5. Main stream media still take it as Ponzi scheme.
6. Big Cooperation are more interested in their own private block chain and token.
Just want to make a few comments for discussion, as some of those points are kind of cliché and not often discussed.
1. I think that hold mentality is not bad for adoption. Saving money is good, and people always saved money. It´s a kind of adoption IMO. The holder is just not spending the bitcoin now, but he is ready to if he wants.
2. Even though web wallets are not the safer option, they are good for adoption. Common people, especially older people (at their 50s for example) are much more used to an e-mail access than to a private key etc... BLockchain.info , for example, allowed thousands or even millions of users to create a simple wallet and use it. Ofc you will not put thousands of dollars there, but for a few bucks its perfectly fine. Easy to use, and great for newbies.
If somehow his wallet is hacked, it´s bad for adoption.... but if wallets such as Electrum were the only option, only a few crypto nerds would adopt bitcoin.
3. About this point, I will quote my own post:
Personally, I think scalability became a marketing, just to make people invest in vaporware coins. Such as bch and nano.
Beating Visa in transactions is possible. But can it beat BTC in decentralization at the same time?
There is no reason to have a global cryptocurrency if it is centralized, owned by a company.
Additionally, being able to scale to 10k tps is not a reason to use it.
Let's suppose I created a website that allows to have 1 million users online simultaneously. Will you visit it?
If you are worried about blocktime, you can just buy some LTC. LTC is a BTC with one block per minute (basically). If you think that´s a game changer, LTC would be the way to go.
5. This is true, mainstream media is not a fan of bitcoin. I believe that with the advent of internet and social media networks mainstream media is losing its power. We just don´t need them anymore.
Take a look at what happened in US elections for example. Trump was cursed 24 hours a day by the media, and he won. Trump now just call mainstream media "Fake news" , refuses to answer their questions and talk direct to the people using his Twitter account.
We just lived the same situation now in Brazil. Bolsonaro (elected president) talked to people through facebook and youtube, as mainstream media was strongly against him.
Not just in politics, but in many other areas as well. I don´t even read mainstream media anymore, as I have plenty better options online.