@lazyboy97o you seem like you have a decent understanding of WDW history so I'm surprised you're missing the mark so badly on this one. Why do you have to take the monorail or ferry to get from the TTC to the Magic Kingdom? To separate the "real world" experiences of driving and parking from the fantasy world experience of the Magic Kingdom. The driving and parking (i.e. the transportation TO the park) was always outside of that divide. The line being drawn at the theme park and not the Resort entrance has always been the case.
The main reason for the TTC is that Walt's site choice had a swamp right in front of it, so they couldn't build a parking lot right in front of it like at Disneyland. They simply decided to use some of the ideas that were meant for EPCOT city in solving that issue. So they dredged the swamp and used the earth to cover the utilidoor foundations and created a lake.