Right. You don't need a particularly sophisticated database to serve the workloads required by a typical website, even a popular one.

The capacity for a specific purpose is not demonstrative of an aptitude for that purpose.

With today's computers and the simplicity of most websites so could be said about flat text files or even XML-files queried realtime trough Xpath or Xquery

That does however not mean I would tout those technologies as good general databases.