It all been said about engines, but never forget that the rest of the bike needs to be bedded in also. Tyres need to be scrubbed, brake pads, suspension and shocks linkages all need time to bed themselves in and loosen up. Agree engineering processes have come on leaps and bounds over the years, so has oil and lub technology. l've was told that if you run a motor in on fully synthetic oil it will never fully loosen up. I can remember that Kawasaki engines used to be notorious years ago for glazing there bores due to being used to lightly whilst running in. Me l've always just ridden the bike normally shifting up early and keep the revs way below the red line until after the first service. And never lost an engine in almost 40 yrs of riding