I think the only reason it may never happen (most of it anyway) is people's perceptions. You think that it's all toasty in the winter in Orlando and LA.
Let's take Anaheim and Disneyland as an example. Most of their patrons are local residents that use Disneyland just like we use PKI. The economic and marketing basis for both parks is virtually identical.
Secondly, you think people wouldn't like it outdoors in the winter because it's cold. In Anaheim, when you go to Disneyland for Christmas, they are bundled up in ski suits because to them it's so cold. We bundle up the same here. The only reason people wouldn't come to something like that at PKI is because of preconceived perceptions and ideas, as perpetrated in this thread.
I'm not saying PKI should be open year round - you can't run Son of Beast and other rides in 10 and 20 degree weather. At least the shopping/entertainment part of it could operate. I mean, as stated by another user, Covington in Cincinnati is outside and so is Easton Town Center in Columbus.
However, in the summer I do believe, with the crowds involved, that PKI can support a 2nd gate.
Anyone who thinks PKI "can't afford it" is absurd. Have you seen the price of a Coke there? Most companies pay 40 or 50 cents for those bottles of Coke (wholesale) and they charge about $3 to patrons... that alone, with the amount of it they sell, in one day... that would build a new shopping center right there!