You're correct that a real MLB franchise can change its scouting budget by however much it wants every year. But just throwing money into it isn't going to instantly create a strong national network of local scouts (who would base employment decisions not just on salary but also on job security, respect, past working relationships, authority/autonomy, ownership stability, etc.). The imaginary scouts of HBD would go from lousy to great with one flick of a dropdown menu. A real franchise could not have a horrible scouting department in 2016, a fantastic one in 2017, and go back to crap in 2018. The +/- $4M limit creates the same effect. No real franchise is going to ramp up scouting when it has high picks, then slash it two seasons later. Theoretically a RL team could quickly slash its scouting by firing everyone, but that would be development suicide; it would be a decade before top scouts would even think about working for that franchise again.