Scholarship I see as following the realization dharma, not preceding it. Does that make sense to you?
In a way because for example the authors of many of the texts were regarded as realized beings. On the more conservative side, Tibetan teachers will often seem to hold that one has to be a master before one can compose a text. One lama told me this is why they didn't really teach the monks composition/spelling in old Tibet, because they didn't want just anyone composing texts. Some of the greatest lamas had to rely on drung yigs (secretaries) to write their books while they dictated. Fortunately, this situation is changing in the modern period and I know at the the Three Seats of the Gelug tradition as well as Karma Kagyu's Sherab Ling, monks must past exams in composition, grammar and spelling to move forward in their classes. This is crucial as the Tibetan language is very much at risk of dying out in two or three generations.
I personally think that different people work differently. Some people through scholarship learn a great deal about the path and with a structure are more able to cultivate. Some people are not inspired by scholarship until they experience things in their meditation practice that the scriptures explain. There are different types of practitioner.
For me, sweating it out in meditation in Thailand not having studied thoroughly was very frustrating. Now with the structure I have learned from Geshe Sonam and my other kind teachers, I am more effective on the practice side of things and have a better idea of how to meditate. It is also study that made it possible for me to fully comprehend and appreciate the teachings that HHDL gives, for example.
Most of the luminaries of the tradition were householders, whether we talk about Padmasambhava, Tilopa, Naropa, Niguma, etc. in the Indian tradition or Marpa, Machig, Khyungpo Naljor, etc. in the Tibetan
Padmasambhava as an enlightened being with a very specific task, born from a lotus et al I don't think I would categorize as a householder. One Nyingma lama friend in India reminded me also that one of his aspects was that of a fully ordained monk.
I am not sure if we could hold the others as examples either because for example Tilopa was already a realized being and Naropa a high capacity disciple, some say a holy being already. Also, the structure of ancient India (and to some extent modern India) allowed for spritual recluses and madmen. As weird as it might seem, I think the monastic paradigm would be more easily accepted in the West than the crazy fish-gut eating yogi paradigm.
I agree that it would be very sad to lose the ordination lineage, but I don't really think that Vajrayana would be in any danger
Even in the least monastic of the lineages, the monasteries were the treasure houses of knowledge and scholarship, and they in many ways made the activities of the great lay masters possible. That is why even lay lineages such as that of Minling Trichen Rinpoche had monasteries attached to them- because they realized the type of training possible in a monastery formed people capable of maintaining the practice and philosophical traditions of the monastery as well as providing ritual support.