"Allowed to survive" is the wrong approach. "Finds a niche" is better.
The fact that software engineers need to understand is that NoSQL is in no way a replacement for SQL in areas of data with inherent structure. In such areas, the relational model wins hands-down, and NoSQL is a big, heavy foot-gun. The caliber of the foot gun goes up significantly when multiple applications need to access the same data.
On the other hand, the relational model breaks down in some ways in many areas. Some things that you'd think are inherently structured (like world-wide street addresses) turn out to only be semi-structured. Document management, highly performing hierarchical directory stores, and a few other areas also are bad matches for the relational model. Other stores work well in many of these areas, from the filesystem to things like NoSQL databases.
The big problem occurs when semi-structured data (say files which contain printed invoice data in PDF format) have to be linked to inherently structured data (say, vendor invoices). In these cases, tradeoffs have to be made......
I have no doubt that NoSQL is able to find a niche. I doubt it will be one which at best involves inherently structured data.