Because they want to go back to Ekanami and Dhandho and Manuphacturing after giving them a befitting beating.
A proper committed war to either defang them or Final Solution to the Pakistani problem will result in sanctions of overt or unstated variety, loss of investment, dhandho etc aside from the usual results of war like casualties and money being spent like flowing water.
My only problem with the cheese-fire is it was on Uncle Sam's terms, not Pakis coming on their knees and begging us for a ceasefire, which they would have after 3-4 days of intense operations.
Govt objective is to economy maxxx, their objective isn't to put an end to the Paki, or destroy their conventional capabilities in a war, Paki is just a gandu who does ungli to you, then you can't bear and give him a good thrashing, then you go back to your bijness, while he copes and seethes in poverty