you need to realize lua isnt targeted as a batteries included platform, its design philosophy is minimalist, not junk included but customize for your requirements. where lua absolutely excels is when paired with C (not C++) and not used as "scripting glue" but fully integrated and
driving the system. it really appeals to minimalistic / keep it simple philosophy guys which isnt the web community.
lua is not a one stop shop and will never be, which probably why it flys under the radar so much - you cant stamp a powered by lua logo on it.