Why do you always blow things up to extreme takes to make other peoples opinions look extreme? Why did Walt have a track put into JC when the skippers could just steer? Practicality, just like automatic the throttle would do.
As to why he didn't automate the throttle in 1955... I assume the technology just wasn't there yet. Unless someone can point me to a water based attraction from that time that used multiple vehicles and didn't just have the vehicles bump into each other (like pirates, small world, ect).
Anyway we are WAAAAAAAY off topic