The current ecosystem of Blockchain technology is not at par with its web2 counterparts. The first concern of Blockchains is around scalability. There has to be a tradeoff between security, decentralization, and scale. This is popularly known as the Blockchain trilemma. Secondly, blockchains are more of a social experiment than a tech experiment. Say even if you create a trustless system between different parties, it will still demand those parties to use it. Otherwise, it is as good as nothing. There are also risks associated with the 51% attack. As quantum computing kicks in, there is a possibility that some nodes can gather 51% of the computational power and compromise with the system. Although some of these concerns have been addressed through major structural updates of many chains, like the recent Ethereum merge, there is still a lot of work to be done.