I'd like to point out that a LOT of the "fancy mysterious" forging techniques developed in antiquity were to compensate for the quality of the alloys available in those eras.
I suspect that a modern alloy forged sword, even without the fancy secret techniques, will stand up to any of the ancient blades you might come across.
Not really true. Many of the techniques were structured to work the lesser alloys out of the metal, enhancing the perfection of the core metals. (Here).
Er, how does what you said disagree with what I said?
They started out with lower quality metal alloys. The special forging techniques both helped to refine those alloys (mainly by adjusting carbon content), and created structural reinforcement due to the folding.
However, they simply did not have the kind smelting techniques we have today. A modern forged sword, even without folding techiques, is inherently going to have better metallurgical properties than the old steel. All that fancy folding to create specific ratios of metals and carbon just isn't needed these days, we can produce steel now that already has those properties to start with.
That's not even counting the modern metal alloys and treatments that have developed since then. Vanadium, titanium, tungsten, cobalt, magnesium, etc. - most of these things were unknown to steel alloying before the 1800s. There's heat treatments and hardening techniques developed in the last century that could fill textbooks.
Heck, I'll take a sword hammered out of a truck leaf-spring against a Damascus blade or katana.
-karma