MMain problems of blockchain networks - especially public ones - fall into scalability. Scalability has become the key point since the main part of public blockchain networks are designed to cover financial needs.
For example, Visa can handle around 24,000 transfers per second and 150 million each day, PayPal is recognizing up to 200 transfers every second and more than 5 million per day. Ethereum blockchain network can process up to 20 transactions per second nowadays. This makes the necessity of exponential up-scaling of Blockchain network platforms obvious.
If we are talking about private blockchain networks with the progression of the 4th Industrial Revolution technologies, we are to mention IoT (Internet of Things). It is meant to operate on top of Blockchain networks because of security, distribution, robustness, stability, delivery, glassiness, anonymity and reliability.
And that is where the scalability problem appears as critical, for example, centralized solutions of IoT transactions operate with millions of them now and it should be said to be a large capability issue when IoT based solutions gets connected to Blockchain platforms and decentralized systems, since transactions amounts per second are very limited.