So, as I understand it, on the western front in WWI:

Warfare heavily favors the defensive, breaking through requires huge casualties for small gains.

The allies have more men, suggesting the opening of new fronts and spreading of troops would be beneficial to them.

Britain is stronger than Germany at sea.

I know there were also u-boats, so Germany would be a difficult target, but Austria-Hungary had a pretty long coastline not that far from Italy, and they managed to send men to Gallipoli, why not there? As I understand it, Gallipoli was pretty rocky and easy to defend, couldn't they have found a better place in Austria-Hungary?