Suspension damage, check periodically

Isn't the suspension system regulated by antbody? They are an accident waiting to happen. I have a 2006 Copper Canyon Sprinter 5th wheel(keystone product) with about 40,000 miles on it. I am in the process of replacing the shackle link plates, bolts, equalizers, etc. The bolt holes in the shackle link plates are worn to about twice their normal size. There's hardly any metal left around the bolt holes. You can't see how badly the bolt holes are worn with a visual inspection. The bolt head and large nut cover the holes. It's taken 3 orders and 5 weeks for the same shackle link kit to almost have enough parts to do the job. First kit was missing 7 parts, second kit wasn't even for my 5th wheel, third kit has parts in it that are not for my 5th wheel. I took some of the parts from the first kit and some parts from the third kit to cobble together the right parts. Now I find out that the leaf spring bushings are not part of the kit. Sold seperatly. Unbelievable! Now I can wait another 7 - 10 days for those to get here. Back to my original question. Seems to be a design flaw when parts wear that badly. Unfortunately, I'm not in a position to replace the axles and suspension system like I would like to do. Would probably aleviate my tire wear problems too.