Only so much that can be gained by refining one technology until the next revolution occurs
I agree with your assertion that a given technology can only be refined so far - propeller driven aircraft were refined and refined with ever diminishing returns, until of course the jet engine revolutionised what was possible.
Your article provides a great explanation of the "law of Physics" limitations of relational databases, but the laws can be changed with a genuinely new technology.
The "cognitive systems era" and IBM's Watson is just such a new technology and Watson is entering its first wave of commercialization - to quote El Reg
"IBM is looking ahead to a "cognitive systems era" in which machine learning and multi-modal decision support systems help banks and investors make better financial decisions, help doctors make better diagnoses, help lawyers make their arguments (rather than just root around like a search engine in briefs for precedence), and help companies do telemarketing by adding computer-assisted persuasion to their call centers."
This 'Jet engine" may only be entering its first wave of commercialization, but the revolution is coming and the "law of Physics" limitations of relational databases will surely be overcome.