That is an interesting scenario to say the least.
So if Oswald kills Walker does Oswald then kill Kennedy?...unlikely...
So Kennedy does not become a martyr ...
At the time it looked like Kennedy would lose reelection...
but either way...no Johnson becoming president in 64...
So Vietnam plays out differently...
So then no Nixon in 68?... So no Watergate in 73?...
So no Carter in 76 in reaction to Watergate?
So then no Reagan in reaction to Carter?..
So..no fall of the Soviet Union from Reagan standing up to them?
And on and on and on...
Could all that pivot on a little strip of wood in a place in time and space?
Interesting to think about