Unlike the base layer, the LN uses source routing: which was abandoned years ago. Requiring the endpoints to know the structure of the network graph leads to intractable routing problems at scale.
Many source routed networks work fine, including Tor. All MPLS usage is source routed. Source routing isn't used for _IP_ (generally) but for reasons which have nothing to do with 'scale'.
Not a problem if you don't intend to have nodes sufficient to actually be considered "at scale" and your plan from the very beginning is a centralised hub and spoke network.