your example is just common sense and looking at what each company has done in the past. Universal announced a second park (meaning people on a week trip might spend only 5 days spending money at disney instead of 7) and disney rushed out hollywood to make you want to stay at disney and maybe take a trip to universal. Many people see either AK or HS useless so in a way disney has 3 parks worth going and universal is getting 3. Now people start to think about reducing how much they stay at a disney resort and spending less money (and getting less people making universal sharing the same number of visitors as disney). How would you plan an orlando theme park vacation if disney still only has 4 parks but universal has 4 also?
You also have to think of what is coming. It's star wars, it's 1 land, part of 1 park... some people who aren't disney people are going to view universal as more of what they want in a theme park and disney is going to be 1 park with part of it they want to see. Same is going to happen with pandora and avatar lands. Universal is also looking at a moderate and lower cost places to stay. I predict that next summer, we're going to see a major up tick at universal and being ask questions about the best way to day trip to disney for a day. Pandora is going to bring some people in, but are they going to stay at disney that they didn't like before or are they going to stay at universal and come see pandora for the day and only that.
I predict that we're gonig to see some major expansion in the thrill ride area all around disney property and wouldn't be shocked if the 5th gate is mostly thrill rides if disney heads that direction. Universal is better setup for that 18-34 year old in my mind and when you bring in action properties like pandora, star wars and the such, business as usual is just going to make universal more exciting especially when it's 4 parks vs 4 parks.. Also do the math, do you have enough time to do 8 park days on your week vacation?
things are changing, this is really exciting!!!!!!