The reality is that informal etiquette is a FAR more effective gatekeeping tool.
Informal etiquette can't be learned except through exposure and experience. You either know it, or you don't. If you don't it immediately sets you apart.
As with Eliza Doolittle, someone who was gatekept out who go access to lessons and tools could bypass the gatekeeping of elitist formal etiquette. There is no bypassing the gatekeeping of informal etiquette.