Why was the 25th amendment necessary

Becasuse if the president was assainated the world would be going into another great depression because the us government would be going crazy trying to find a replacement for the president so if they had never created the 25th amendment we would be messed up. and the next person to go into office is the vice president then the speaker of the house I believe.

Because we'd be screwed if the president died and we had no one to run the country.