India just filled the vacuum we made. I hope you're familiar with the Iran-Pak timeline during the 90s. Their Diplomats getting killed in Pakistan, Ambassador getting shot dead in Lahore, 19 Air Force Cadets getting slaughtered, Cultural Center being torched and stormed in Karachi. Do you think all that is taken fine? I am not saying Iran is an Angel but what we let Saudi Agents do to them was something much enough to curb diplomatic relations which they didn't.
They were also helping us with Kashmir Issue. Iranians let ISI, use it's territory to train Kashmiri Mujahideen, assisted them in Kashmir through their channels. Surprisingly, agreed to shift all our Air Bases in Iran in case of War with Pakistan (mentioned by Gen Asad Durrani and Aslam Beg). They also arrested RAW Agents in Iran including their Station Chief (ask me for the ref if you want for all this). What we did? We applied on the US Sanctions, stopped importing oil from Iran, stopped exporting rice, wheat and oranges.
In clear words, we ditched them when they needed us. India came to their rescue at that time. Being the only Iranian buyer under sanctions!