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Question/Instruction: How have synthetic cork manufacturers addressed the technical problems associated with their products, according to the article?

Given material: According to legend, the idea of using a chunk of bark from the cork oak tree to seal wine bottles was the brainstorm of Dom Pierre Perignon, the blind 17th-Century monk who invented Champagne. Until then, the world had known only primitive closures such as hemp soaked in olive oil.
In truth, Perignon did nothing more than popularize the use of cork, which had been known since Roman times. However, the story does reflect an important fact--the widespread use of cork began three centuries ago.
Since then, only one other closure of merit for wine bottles has been developed: the screw-cap. Scientists consider it the perfect closure, but it has scarcely ever been used on fine wine. It has odious associations with cheap stuff that no one considers worth aging.
Consumers are now starting to find bottles sealed with something new. Two companies making plastic stoppers that retain the traditional elegance of cork (at least they still require a funny tool to remove them from the bottle) while eliminating, the companies say, the inherent problems of natural corks.
Synthetic corks have been around for more than a decade, but they don't appeal to the tradition-conscious wine industry because they aren't natural. However, every winemaker in the world knows that natural means potentially ruinous. A significant percentage of natural cork is flawed and can impart an awful, moldy smell ("corkiness") to wine.
By some accounts, as much as 8% of all cork-sealed wines may be "corked." The cork industry itself concedes that at least 1% of all corks are guilty of causing corkiness. My tests over the last eight years factor out at just over 2%.
"If I were building automobiles and I knew that 2% of all cars off the line were lemons--well, the public would be on me faster than odor on manure," says Doug Meador, owner of Ventana Vineyards in Monterey County.
Meador is one of the small number of U.S. winemakers--under two dozen--willing to boldly go where fine wineries have never gone before . . . into the world of synthetic corks. Well, somewhat boldly; most are taking this step tentatively. Meador is using synthetic corks only on wines he is certain will be consumed young.
No one knows the long-term effects of synthetic corks on wine aroma. It's nearly certain that there is no chance of corkiness from artificial corks, but there have been random reports of a plastic aroma.
Moreover, it's been said that some plastic corks have been difficult to remove from bottles, that one popular type of corkscrew (the two-pronged style known as the Ah-So) doesn't work particularly well with them, and that they aren't well suited for imprinting with a winemaker's brand name.
The two largest producers of synthetic corks, Lermer Packaging of Garwood, N.J., and SupremeCorq of Kent, Wash., say those problems have been resolved. They say their products now look like cork, act like cork, make a better seal than cork and wipe out the cork-taint smell.
Those who use it agree. But there are literally hundreds of wineries that won't risk the consumer backlash against what they call the plastic cork. About as many wineries are testing plastic corks, though. And some wineries are considering using colored corks in clear glass bottles in order to display the un-corks.
So far, the only winery to switch entirely to synthetics is St. Francis Winery in Sonoma Valley. It tested synthetic corks a decade ago, when the first experimental versions were available. Winemaker Tom Mackey says he liked them immediately, despite the technical problems--some early synthetics were beaten up by the bottling line machinery, with the result that they didn't make a perfect seal.
What he liked about them was not just the freedom from corkiness. "There was more freshness," he says, "and we held that freshness longer."
The air trapped in cork bark cells can accelerate oxidation, so winemakers normally add a tiny amount of sulfur to young red wines to protect them. "The Cellukork has no cells with air trapped inside," says Mackey, "so there's no need for as much sulfur. What I've done to compensate for that is that I'm cutting down on the free sulfur I use at bottling." He says the wines have proved to be stable even without so much sulfur.
In the newest formulation of Cellukork, Lermer adds a tiny amount of sulfur dioxide to retard even trace amounts of oxygen found in the resin, making the synthetic cork a nearly perfect seal.
Mackey says the synthetic cork works better for young white wine to retain its fruit longer, but it also works better for wines that are to be aged. "One thing that we've strongly suspected is that the aging process is greatly retarded with the Cellukork," he says.
This prompt doesn't seem malicious.