Their will always be a need for both. SQL will be better at some things and NoSQL better at others. Use them both, just pick the correct one for the correct job. Thinking the data is going to change all of the time with little thought is a silly argument. With professional agile teams making development decisions, there is a good deal of planning and thought that goes into system changes whether the database requires it or not. I have created structured data in NoSQL and virtually non-structured data in relational databases (simply tagging back to the id). They both worked great. We will continue to see large advancements in both technologies as SQL works to scale horizontally better and NoSQL continues to develop better querying technologies. I predict that SQL and NoSQL will merge in the middle as these two technologies continue to work toward each other.