Utility is good enough for engineering but not for science. The methodological problem with the truth was that one can arrive at the truth but can never be sure because it is always possible that someone else finds a better theory that contains one's theory as a limiting case. Because of this Popper developed the concept of verisimilitude.
Newtonian physics was considered true and corroborated beyond reasonable doubt until Einstein showed that things become very un-Newtonian at high speeds. So Newton became the limiting case for low speeds of General Relativity Theory. Relativity Theory is closer to the truth. It can be taken as the truth until somebody else comes up and shows that relativity theory is a limiting case of the Theory of Everything.†
Your conclusion: “The Newton-Einstein comparison also shows that science is not about proof or Truth.” is absolutely false. What do you think physicists are doing at CERN? It is all about proof.††
A well-known irony in the history of science was that Ptolemy's theory was even superior for the purpose of navigation in comparison to the newly developed Copernican theory. Despite its practical usefulness, Ptolemy's theory is false according to scientific criteria.
To replace truth with usefulness is exactly what Blaug characterized as playing tennis with the net down.
It is surrealistic when economists discuss truth because after 200+ years they still cannot tell the difference between profit and income (see 2014).
Kakarot-Handtke, E. (2014). The Three Fatal Mistakes of Yesterday Economics: Profit, I=S, Employment. SSRN Working Paper Series, 2489792: 1–13. URL