To my mind, Gombrich's lecture is really him just pointing out the elephant in the room.
Ajahn Brahm made the comment once in an interview, to the effect that "we have the best product. (he was speaking of religions and spiritual instruction). We need to promote it." I am paraphrasing what Ven. Ajahn Brahm said. Ajahn Brahm may be speaking of, and he himself representative of, the emergence of a modern Theravada...firmly wedded to the orthooxy, but not afraid to venture forth into the world, and share and promote, and indeed act with engagement, through what is known in the Tipitaka.
I live in the US. In this country, Zen has a foothold due to its emergence during the 1960's the time of the beat poets, the hippies, the Kerouacs and the Ginsburgs. Motorcycle Maintenance. Vajrayana took hold through the evangelism of the misogynist and alcoholic (sorry) Chogyam Trungpa, who brough "crazy wisdom," and other forms of tantric and ecstatic ' Buddhism.'
What did Theravada have to present? Theravada really didn't come to America. Rather, folks like Jack Kornfield went to Thailand and lived with the snakes, the scorpions, one meal a day of boiled frog soup, and Ajahn Chah. Theravadins like Dr. Kornfield and Ajahn Brahm came back to the West, and have somewhat quietly illuminated the field.
Zen offers flower arranging, kyudo, and anything cool or trendy has a "Zen flavor." Vajrayana offers Green Tara and tantra. Theravada is a steaming bowl of boiled tree frogs.
Well, being trendy and Zenny doe snot bring us closer to Dhama, and tantra may be fun, but it's not Dhamma, either.
What Theravada needs to do is what Ajahn Brahm is doing...break out of the mold a bit, offend some of the hierarchy, tell some jokes, engage with people, and really make an effort to help people understand that that the boiled down form of Buddhism, the Tipitaka, holds the key to freedom from suffering.
If Richard G needs any inspiration for what the solution may be to the problems he raisis in his fine lecture, one example of the path forward is Ajahn Brahm. There needs to be more like him.