It's really all about market research. This site is such a microscopic view of what people really want. Of course if you asked anyone on here what they would want, they'd say they want a 250ft tall Intamin with 15 inversions. This of course is coming from a demographic that's mainly males between the ages of 16 and 30, a lot of which don't have families. PKI does extensive market research to find out what types of rides, shows, and attractions would be the most popular with the most amount of people from year to year and they follow that when planning their expansions. IJ isn't exactly what people on here would describe when asked what their dream coaster would be, but to my understanding, it has been very popular with the masses.
I do however agree with your comment that you made before that PKI is always removing family attractions. Looking back at the timeline, the last true expansion we've had was SOB in 2000, and even that's arguable because the monorail used to run there. Of course, there are several reasons why this is happening. The main reason is likely that things get outdated and the space that they occupy could be utilized better and be more profitable with a new expansion, there's no denying that. Secondly, let's face it, when some of these rides get old, it's just really expensive to maintain them and as opposed to cutting into their budget for the next year, they just remove it and utilize the money on other improvements. Lastly, PKI has a pretty good layout. To my understanding, the "wheel" design is based off of Disney. Let's face it, in those few areas where it dead ends, it's always crowded (i.e. AZ neear SOB, CM near Spongebob), so in order to add a new attraction in an area that's not preexisting, they would almost have to ad a new area, which is real money there. I just wish they would think a little more when deciding what to remove. Regardless of of you feel about the Tiques, Flyers, or IJ, this years expansion really took away from the look and feel of the park.
I was going to say the same thing. If you look on the map you see that people can go in a circle around the park going on every ride (exept AZ).