Yes it’s expensive, but if we also offer to build similar missile cities to the Saudis (who have a considerable mountain range approx 150 km north of Riyadh), who are looking for a way to deter Iran (and any others with nefarious plans against them) as our defense alliance partners, we would gain the expertise, technology and possible some funding assistance to do it in Pakistan. If Pakistan is ever called upon to employ kinetic means against an adversary of the Saudis and the Pakistani state agrees, having the missile bases inside Pakistan would be just as capable as having those bases inside Saudi, so conventional missile bases in Pakistan could be of use to the Saudis defense as fulfilling the spirit of the defense treaty.
Spread over the next 5-10 years, much could be built and could help employ a lot of Pakistani people, in Pakistan and Saudi.
Under the auspices of “mining”, much joint cooperation could be done.