One of the bigger problems with blockchain is that there aren't many field experts working in the space. For example if you look at a voting blockchain you will be hard pressed to find an experienced psephologist working with the team.

Without experience most of the team is made of people who might have read up on the topic and thought - "Well! This can be changed via blockchain". What they don't realize is academic exhortations are vastly different from practical implementations.

For example, if everyone could implement that amazing trading system from that trading book, everyone would be millionaire. But that is never true. Another good example of this is the mistaken understanding of banking and especially Visa:

https://www.forbes.com/sites/francescoppola/2018/04/21/bitco...

What this means blockchain solutions either run into issues during build or work in a very specific circumstances.

For example, the building block of most cryptocurrency is game theory - if someone takes over 51% then rational economical thing to do is continue the chain. But what if we have an irrational actor who doesn't care? Or what if people can manipulate the change even below 51%. A good example is the F2Pool's manipulation of Status ICO with 25% hash rate:

https://themerkle.com/f2pool-allegedly-prevented-users-from-...