Well, my title is a little cheeky but I think it's fair to say that if physicists and engineers actually knew what quantised inertia predicts, that they just can't, then they'd start work on it tomorrow. So here is a sort of abridged summary:
QI predicts the recently-observed cosmic acceleration perfectly without needing any infusions of invented dark energy. QI explains why the universe is flat (PE=KE) and always has been, so gets rid of the need to imagine our particular era is 'special'. QI predicts the value of the gravity constant G from the cosmic mass and scale and speed of light. This means that physics has lost a free parameter and has become simpler for the first time since 1905. QI predicts galaxy rotation, and specifically why the oddities always begin at a particular acceleration. MoND has to input this acceleration, QI does not - it predicts it itself. QI further predicts the observed variation of this critical acceleration with cosmic time. QI predicts the low-l CMB anomaly in which it looks like the longest waves in the cosmos are smoothed out, and the CMB peaks as well, but not their heights. It predicts a relation between the area of something and its mass. QI predicts the first, and a few others of the quantised redshifts seen by Halton Arp - the others may appear when we look at other electron transitions. It shows why the Magellanic clouds appear to have broken free of the Milky Way but have left a 'stream' behind them that curves around the galaxy implying they are still bound. QI predicts the motion of wide binary stars which show identical anomalies to galaxies when they are far apart, and orbit below the critical acceleration. Dark matter can't explain them because it can't be packed into the small scales of binaries and still predict large galaxies. You can't have it both ways, so dark matter can now hit the road. QI predicts the very beautiful shape of Hoag's object which is almost like a poster child for the theory. It predicts the orbit of our neighbour Proxima Centauri, which is orbiting far too fast, just like those wide binaries and the larger galaxies. QI predicts the bending of light by the Sun, just as general relativity does, but it is successful with galaxies too, which GR is not. QI predicts relativistic jets in galaxies and so gets rid of the contrived & complex, and conveniently invisible, black hole explanation. QI predicts the Casimir effect, the emdrive, Mach effect thrusters and the asymmetric and symmetric capacitor thrusters that half the planet thinks are hoaxes and half think are the saviours of mankind. It predicts some aspects of the Podkletnov gravity shielding effects, which are much maligned but were published in good journals and have not yet been falsified. QI predicts the test results from my lab in Spain who observed thrust from a laser loop, shielded on one side. If this is confirmed then we become an interstellar species, which would be timely! QI predicts the photons seen coming out of the Dynamical Casimir Effect. It provides an explanation for cold fusion, or LENR if you prefer, and for the excess light seen coming out of nanocavities. A new source of energy from the vacuum? Similarly it predicts sonoluminescence. QI provides a new way to understand pair production and it predicts the ratio between the proton and electron mass, and the Planck mass. QI provides the first ever intuitive explanation for inertia which has always been brushed under the carpet in physics.
To finish, QI is conceptually challenging but technically very simple & can be used to predict a massive range of phenomena. I am writing a book to detail all this which might be called 'The Empiricist Strikes Back' or 'How to Predict (Almost) Everything'. Now I should say that of course I do not necessarily believe every anomaly listed here, but I think this list, which has taken me 15 years to present, implies something!