I disagree to a degree. Plain bearings rely on precise clearance to work. Too much, and oil pressure can’t develop adequate film thickness, resulting in metal to metal contact. Not enough, and the same thing happens, but for a different reason - there’s not physically enough room to develop film thickness. In an old engine, plain bearings are generally worn so that the clearance is getting to the maximum limit. Open throttle, high RPM (very rarely are you not at WOT when you approach redline) is when the loads on those bearings are the highest, and significantly so. If your engine has lead a hard life, limiting RPM can prolong it’s life some. How much? Maybe not enough to matter. I’ve never seen data on that, but in theory, it could matter.