I’m going to go against the grain on this one. Yes, drain plugs do wear out. Take any bolt and loosen and tighten it dozens of times, sometimes blazing hot, sometimes freezing cold, and sometimes something is going to go wrong. It’s not a perfect world. That’s why shops that do oil changes keep new drain plugs in stock. Whenever we do an oil change if the threads or the head of the drain plug show any wear or damage it gets thrown out, we install a new one, and add $5 to the bill. Quick and simple, and avoids damage to the oil pan by using a damaged drain plug.
There are also usually easier and cheaper ways to repair a damaged oil pan than replacing it, as has been noted above.