As nice as it sounds to have a Disneyland/ Disney World would be, you aren't missing much when it comes to having one. I live about 17 miles from Disneyland, and have been a handful of times. Its expensive, they go up in price every year. As a SoCal resident, I get a discount, I only have to pay $98 to get in, and that is on a off day.(they have a new pricing chart, where prices depends on the time of year/day.). So off/slow days are cheap, but popular days/summer its way more expensive. I think its like $120 per a ticket on busy days. Plus the crowds, waiting in line for rides, food is expensive and not good.
Then again, I am not much of a theme park fan......
I've always been something of a theme park junkie.
We still have Kings Island, Coney Island and The Beach still operational here. Kings Island and The Beach are only about 20 miles away and Coney Island is about 35 minutes away. The Beach was closed for several years but recently reopened and Kings Island attached its own water park. Coney Island is much smaller in scale than Kings Island but still enjoyable to go to as an alternative to KI. We used to have more amusement parks with another water park called Surf Cincinnati and Americana Amusement Park/Lesourdsville Lake & Fantasy Farm (two parks right next to each other). All 3 of those have closed down in the last 20 years though I still have fond memories of when my dad would take my little brother and I to Americana & Fantasy Farm for the day.
I managed to knock Walt Disney World off my bucket list last year when we went down for vacation. Being both a theme park junkie and a Disney junkie; it was nice to finally set foot in the park after decades of wishing to be able to go.
Disneyland has now replaced Disney World on my bucket list so someday I WILL make my way out to California and go there.
Back on topic regarding a Disneyland in the Middle of America...I did some research and discovered there's a few amusement parks in a nice little three-hour triangle of St. Louis-Kansas City-Branson. St. Louis has Six Flags, Branson has Silver Dollar City, and KC has Worlds of Fun/Oceans of Fun. It would seem to me that Disney might not want/be able to just plop an amusement park down in that part of the country. I mean they could but I would think a lot of locals and those other park owners would be crying foul to their state legislature.
I think a more appropriate question might be why hasn't WB managed to ape the success of Disney with their brands? They have DC Comics, Looney Tunes, and Hanna-Barbera at their disposal and at one time owned the Six Flags chain of parks (and they used to own Nickelodeon once upon a time) but they seem to do nothing but trip over themselves in regards to building their brand.