I think what I and any one of us in the space should do more often is talk about cryptocurrency and blockchain with mainstream people both online and IRL. That is the way we who are throughly immersed in this subject matter can get an idea what's really holding back the industry. That said, public blockchains other than Bitcoin have only existed for not longer than 5-8 years. The industry is still very new.
Based on my listening to mainstream people IRL and reading what blockchain skeptics on Quora have had to say about it, the main obstacles are ignorance or misunderstandings, fear of sovereignty and poor user experience.
Ignorance and misunderstandings can be corrected by disseminating correct information. For example, if someone has only heard about Bitcoin has a very vague idea of what cryptocurrency or blockchains are, that can be explained. The technological basis of cryptocurrency in particular is easy to understand at a crude level because it's all founded upon distributed ledgers. A distributed ledger is simply a ledger copies of which are held on many computers simultaneously where the correctness of a ledger is decided by group consensus. Thus no central source of truth is not needed.
Ignorance or misunderstandings
One group is blockchain critics who consider cryptocurrency to be the only possible use case of blockchain. Some can be quite vehement, which is obviously a knee-jerk reaction caused by all the hype surrounding many new projects. To a degree these people have a valid point. Not every problem in the world needs to be solved with a blockchain. But many are unaware of some of the specific use cases where blockchains are useful. For example, probably the most convincing argument for Hive is the fact that having one's content and follower information on stored on Hive means sovereignty for the content creator vis-a-vis platforms. Because Hive itself is incapable of censoring anything (except by a supermajority of witnesses and even then only through a hard fork), a content creator on Hive is protected from potential tyranny by a single entity unlike on any Web 2.0 platform. Because of using a variant of DPoS as its consensus algorithm, Hive has high enough a throughput and low enough cost of use to serve a vastly larger user base than it currently does without the costs spiraling out of control. For app developers, it is notable that unlike on Web 2.0 where each app must deploy and maintain a proprietary back end, Hive apps can get away with very lightweight back ends in comparison to Web 2.0 apps. For example, all of the user-generated content is on the Hive blockchain. The good news are that we can remedy this problem by going out and setting the record straight.
Fear of sovereignty
The above brings me to the second obstacle which is fear of sovereignty. The god-like powers of the admins is in the back of the minds of all Web 2.0 users. The users of Web 2.0 are used to sloppy password management because recovery procedures are always at hand. In case of any unpleasantry encountered that goes beyond palatable, the first reaction of a Web 2.0 user is to contact moderators, those angelic creatures whose job is to protect innocent users from bad content or bad people, often prompted by readily-available widgets created just for that purpose. In contrast, Web 3.0 is a domain of freedom and responsibility where no one's hand gets held by authority figures.
It is not surprising at all that cryptocurrency and public blockchain adoption are furthest tech savvy people particularly in the West where individual responsibility has the strongest emphasis in society or in third world countries where the authorities are the most unreliable like in Venezuela. Nigeria is another leader in cryptocurrency Web 3.0 adoption because few Nigerians trust their authorities. Adding to the rise of Africa in Web 3.0 is the rapid proliferation of mobile internet there. Also, the young generations tend to be the largest in Africa.
Poor User Experience
Poor user experience is a direct result of the immaturity of the industry. It is most likely to the easiest and the most straightforward one to fix. It just takes some UX expertise and more developers starting to take them seriously. It is not enough to cater to an expert user base. But from what I've take place on Steem/Hive in the last 1-2 years, things have improved vastly and I'm convinced they will continue to improve further.
The fear of sovereignty is the hardest one of the three to fix. It's a philosophical and temperamental problem. The fundamental problem is with the people themselves. In my view, centralization of power is the root cause of all the greatest tragedies of the last 100 years. Those aspects that feed into the fear of sovereignty like the management for and full responsibility for one's keys can be fixed successfully to a large degree as the example of Hive Keychain demonstrates. This is where great UX design can do a lot of good. There are all sorts of solutions from centralized password protected vaults to integrated password management software that can be applied.
There still are existential risks to the space as Russia's recent strict anti-crypto legislation demonstrates. In Russia, a bill has been drafted to ban the use of cryptocurrency as a means of payment. Cryptocurrency mining will be hard hit by this, if the bill is passed into a law, because cryptocurrency miners are paid with cryptocurrency for their work. The Governor of the Bank of England has proposed the development of a global regulatory framework for cryptocurrency. The latter would be even worse because it would be an attempt at reining in cryptocurrency through a newly created centralized structure. It is not very concerning how some individual country, be it even the USA, regulates cryptocurrency because the world is a very large place. But when major figures in legacy finance start talking about a global regulatory framework, it is a potential problem. While global regulation might improve chances of adoption, it could water down the purpose of the entire sector.