As I was watching Jonathan... the concept that kept coming to me repeatedly was that of "rooted." Liturgical art, as well as liturgy of worship itself, is something that is meant to be "the work of the people" and as such conceptually is always rooted not just in the transcendent experience of God, but in the work of both the individual and community in their participation together in the real life in which God encounters us.
It strikes me that some of the mess that is contemporary art is that it is seen as first "self-expression" and perhaps even more something requiring the "informed/educated/specially trained/ or positioned" to interpret it for another. Liturgy / liturgical art derive their power and meaning through the ways they are meant to become a living rhythm for the participants... a living invitation to step into life that is both rooted and transcendent simultaneously. Remarkably tue particularly in liturgical worship, but I suspect equally true of liturgical art is a very clear understanding that without the participant themselves, it does not exist. There is no worship without worshippers... there is no prayer without "pray-ers"... there would be no liturgical arts without both those creating them, BUT also those beholding them. I know of few things that by their intent seek to create this kind of relationship and invitation.
As I listened to Jonathan... I keep hearing Augustine's statement of the "heart always being restless" until it at last finds it's rest in God. The way that the medieval arts drew complex meanings to create a cradle of meaning into which one not only was invited, but encouraged to inhabit as a rhythm of meaning and life seems to be an attempt to put practice, visuals, spaces, community, and even worship itself into the kinds of patterns that might indeed allow one to experience God and therein find rest at last.
Could the current art culture benefit from helping people and communities find "home" again... I cannot help but think "yes." Unaccounted for though... would be the power of another theological category "sin" that also plays out in the human creature that takes the kinds of things that are life giving and warps them into something less so, if not outright destructive. It is that destructive aspect that I think Jonathan's first half and critique of contemporary art culture revolves around. It is that reality that will work as a counter agent to those like Jonathan and it sounds like yourself as well in seeking a "better" way forward.