Used DP Reliability

I thought our Cummins would last to 250-350K w/out major repairs. I have done all regular required maintenance over the years. Last 18 months have replaced the following: exhaust manifold, new head, high pressure fuel pump. lift pump, fuel lines, turbo charger, hydraulic pump, shocks, muffler, fuel pump sensor @ $$$$$$ cost!!! That doesn't include being hit w/ Hail storm last July and had to replace the entire roof, ac units, etc, and repaint 2 sides of the MH. Just took it in for a diesel inspection and a driver hit the front and now have a new paint job on the front. Murphy's law? We still love RVing and would not quit for anything!!!