They’re all plotted, but they vary considerably in length so some don’t show up. If you artificially normalise them, they all do.
Without changing any of your other code, replace the ‘quiver’ call with this to see them:
arwlen = hypot(u, v); % Arrow Lengths
figure(1)
quiver(x, y, u./arwlen, v./arwlen);
grid
Apparently, Excel (or whatever you plotted ‘Expected Graph’ with) doesn’t care about the length variation. MATLAB does.