"Bullet Proof" Steel Welded Front Gate not so "bullet proof" after all!

i was really impressed by the workmanship when everything was first installed. How long has it been, five years maybe? The wife asked me to repaint the giant front entrance sliding "doors" to the property. Started my prep, only to find rust through spots. Don't see any drain holes anywhere in the superstructure either. Looks like it would be a big mess trying to repair/patch these two-ton things. What could have been done differently to prevent this? It is a little disheartening investing in prep and paint for something that is slowly going to rot away. Just hope when it eventually falls off its track, it does not fall on any of us.

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