When the Berlin wall fell and the Soviet Union collapsed, the CIA and NSA should have been cut down by 90% and repurposed. The FBI now would be a competing agency in need of political purpose and domestic counterintelligence operations in order to have the best enemies for self promotion.
The FBI's original purpose was to pursue criminals who crossed state lines. The automobile made it easier for bank robbers to rob in one state, then drive over a state line, leaving local police unable to pursue.
Hoover's G-Men had jurisdiction throughout the U.S., so they could purse Dillinger, Bonnie & Clyde, etc. from state to state.