You're essentially agreeing with the author's premise. They're saying that you should think about your business domain problem and choose technologies that solve that problem, even if they aren't the big, flashy technologies used by Big Tech.

If your business domain involves handling peta/exabytes of data, then by all means Cassandra is right for you! Most companies don't handle nearly that much data however, so using Cassandra for a database to manage only a few gigabytes of data is overkill.