If they were to start brewing beers to a similar standard as to the Euro lagers/Pilsners etc. then it would cost as much (or more) to produce than the imported megaswill (better grain bill, imported hops, water treatement, cold fermentation, extended lagering, etc. etc.), and would consequently not sell. There would be no "premium imported" label, and therefore impossible to sell at the inflated price. Unfortunately we're stuck with the substandard quality they churn out in order to maximise turnover, and therefor profit.
Like you, I wish it could change overnight, but I don't think this is ever likely to happen.
It's a sad state of affairs, and there is truth in what you say. But premium beers are not that much dearer these days and some of those are being imported.
So the price difference is not as great as it used to be. Even if they weren't to change over night it would be nice to see them moving in the right direction.