Motor gone because oily spark plugs?

While oily spark plugs can certainly be a symptom of engine issues, they typically wouldn't cause the entire motor to fail by themselves. Oily spark plugs can occur for a variety of reasons, such as a faulty valve cover gasket, worn piston rings, or excessive oil consumption. If left unaddressed, these underlying problems could eventually lead to further engine damage, but it's unlikely that they would cause the engine to fail catastrophically.

If your engine has failed and you noticed that the spark plugs were oily, it would be important to have a thorough inspection performed by a qualified mechanic to identify the root cause of the failure and determine if any other components were affected. There may be other issues at play beyond just the oily spark plugs.