From the way the script concludes, it's obvious that Victor owns A LOT. He has robotics, missiles, space stations, ships and even Latverian Freightliners under his control. So the Von Doom Industries corporation is merely the U.S. facade for a much larger conglomerate. But prior to the accident, Victor really has no reason to build Doombots, or do anything else that could be considered a threat. He's a scientist, well respected and decorated by the world's greatest leaders, and he's simply riding a tremendous wave of success due to the breakthroughs he's managed.
But what I sense from the script and storyboards is that the writers felt that in this origin, Victor simply wouldn't have had enough time to put together a threat large enough to be a challenge worthy of four cosmic-doused heroes. There just isn't enough time in this script for him to come up with all of the traps and technological advances that would afford a non-powered armored man any advantage over the FF (which is why they should've foregone the origin story altogether and just have him established as a monarch from the get-go

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In the script, the organic armor and its subsequent abilities makes Doom a formidable foe that all four must combine forces to defeat. He is more than their equal. It's believable to audiences this way, because frankly, he is a God in Act III--too wise, cunning and powerful for his own good. What's more, he hungers for and enjoys his newfound powers and considers them as gifts from the Gods "bestowed" unto himself. He is meant for royalty, so from his position, this freak accident was bound to happen anyway if it meant upgrading him to the level of superiority where he belongs. All other humanity is simply beneath him at that point...especially the FF when they unite against him for the first time.