I think the key word used in this analysis is that Isreal MUST win . . . To do that it has to accept casualties (high), and is also based on the assumption that Syria and Iran are not willing to accept large numbers of casualties (Iran lost upto a million in its war against Iraq and Syria over 25 000 in it's war against Isreal in the Bekkaa valley protecting the road to Damascus - I think they'll be more than happy to go higher!) another option just give the Golan heights back to Syria for full peace and pull the rug from under the Iranians.
from the article: Next Israel-Hezbollah war will be worse, says U.S. analyst