Answer
The Lord’s descent in such a place is a vast spiritual phenomenon. Unlike a simple temple installation, where a particular spiritual authority may perform the pratishtha, in a place such as the Ayodhya Ram Mandir the devotion of millions of devotees attracts the Lord.
Each devotee has some connection with guru-parampara, whether in this life or previous lives. It is not necessary that a single acharya invoke the Lord for everyone. The collective devotion of countless devotees can attract Lord Rama to manifest for an entire nation.
This is why purely ritualistic objections—such as whether a particular architectural or ceremonial detail has been completed—do not capture the whole reality. Rituals have their place, and ritual experts may be technically correct in certain matters, but Krishna is beyond ritual.
When there is immense devotion, that devotion itself becomes a powerful force in attracting the Lord’s presence. In Kali-yuga, all rituals are performed imperfectly, and therefore we always pray for forgiveness for mistakes in mantra, pronunciation, and procedure.
The extraordinary concentration of millions of people on Rama consciousness is itself a profound spiritual event. Such widespread remembrance of the Lord brings auspiciousness, prosperity, and spiritual upliftment. When Krishna consciousness or Rama consciousness spreads, it transforms individuals and society, and many wonderful changes become possible.