It's technically possible to replace any blockchain with a database but where are you going to host it and who is the trusted central authority?
Blockchain might not the solution but it shows us an alternative to trusting some middlemen that have too much power, instead we trust code that is emotionless, non-judgemental and consistent.
A distributed ledger is more than just a database, it's a technology that can orchestrated trust online without a central authority. That's a huge deal, compared to a sql database that is owned by someone, who is the singularity that administrates the whole thing.