Yes, it's a machine with many moving parts. There's bearings, gears, ball screws, lead screw, belts, etc. There's also multiple precision ground surfaces that w

Yes, it's a machine with many moving parts. There's bearings, gears, ball screws, lead screw, belts, etc. There's also multiple precision ground surfaces that wear unevenly because some parts of the surface get far more use than others. The bed tends to accumulate damage over time, as try as you might, you'll eventually drop something heavy on it. A lot of it is very much fixable, but I suppose that eventually one decides it's too much to bother, especially if something is damaged is badly enough, or the lathe is old enough and it doesn't make much business sense to fix it. If you abuse a machine badly enough you can get something bent to the point it's not really worth fixing.