The devs stated, that they took other transport games as inspiration.
How the f*ck can you not learn from the worst mistakes of your inspirational games?
It is so simple. Speed based on loads screws up the interval between vehicles. That includes loading speed and thus stop duration based on load, acceleration based on load and top speed based on load.
You cant argue that a feature is realistic if the environment/other interdependent factors are not, like keeping a schedule.
Thats not even early access, thats a design flaw of transportation games since at least 20 years ago. Unbelievable.