Honestly , I think that the high value of unconfirmed transaction is the biggest problem in Blockchain , as well, It is one of the reasons for the decreased price in this period.
On the other hand, I guess that the main cause of this problem is the overcoming of transaction in a small time, and that lead to rise in value of unconfirmed transaction. and hopefully that this problem will be solved soon.
This thread was opened at the height of bitcoin price surge, that's why the confirmation is very slow and the cost of transaction is very high. But if you are going to check it today, its down to around 50K unconfirmed tx.
https://blockchain.info/unconfirmed-transactionsIt seems like transactions are now sent much faster and fees have lowered. Although the Lightning Network is still in test phase on the test net, people are already using it, which devs are not so happy with. Because there still some work to do. Hopefully LN will be live soon and transactions will sent properly.
I assumed that more and more bitcoin users are moving to Segwit wallet. Its much cheaper and tx are very quick. Although with the legacy address, its still cheap but not cheaper as Segwit address. And when LN is implemented this whole scalability problem will be resolved.
Which fee should I use?
The fastest and cheapest transaction fee is currently 180 satoshis/byte, shown in green at the top.
For the median transaction size of 226 bytes, this results in a fee of 40,680 satoshis.
https://bitcoinfees.earn.com/