It's important to note that the real Master has always been inside. Even when great initiates have physically taught this science, the real spiritual community has always existed and will always exist within the internal planes. As Samael Aun Weor wrote in The Perfect Matrimony:
Our Gnostic Church is the Transcended Church. This church is found in the Superior Worlds.
While there has been a physical component to Guru Yoga, it more importantly applies to practitioners' relationship to the Inner Master within the superior dimensions. Both Buddhism, Hinduism and Sufism state it is necessary to rely on the teacher, but many students, caught within three-dimensional psychology, only look for physical teachers, ignoring that these principles apply to developing the spiritual consciousness so as to investigate teachers and teachings within the higher dimensions.
Those who work effectively with the practices of this tradition will develop spiritually, granting the disciple the capacity to speak personally and receive teachings from the Guru of the Gnostics. This is what students need to develop in order to advance throughout the path, but to reach this point requires diligence, spiritual work ethic, and the will of God. For a deeper understanding of Guru Yoga, study the following resources: