The primitive technology guy made lime mortar from the shells of rainforest snails

Given that he has access to thousands of years of knowledge then, in theory, what level of technology could he hope to reach? I mean he’s building up a nice little manufacturing base there what with his kilns, water-powered machinery, textiles and such. I imagine it’s a problem of scaling when you only have a workforce of one. Yeah, it’s a pointless question but it’s like watching a person rebuild civilisation after all the infrastructure has failed because there’s nobody left to keep it running.