I believe demand for engineers to solve these problems will wane as the solutions become codified into various open source projects.

Think of how difficult a problem that involved terabytes of data was to solve before the advent of Hadoop and now consider how easy it is with solutions like Spark.

Overall this is a good trend. I'm not saying that $300K engineer salaries are going away; I'm saying high salaries will pursue the engineers who are solving unique and demanding problems.