The founding team of Castled comprises mostly founding engineers from HevoData, which is an ETL solution. Having built both ETL and Reverse ETL solutions from scratch, we have realized that the architecture required to support both ETL and Reverse ETL needs to be drastically different. Your cloud data warehouse is powerful enough to change the entire architecture of the product depending on which side of the pipeline the warehouse is on. So we believe you need different products to support both ETL and Reverse ETL. But agreed the same tool can provide both products.

I will have to check how airbyte supports both. Regarding Castled, Regular ETL is there in our mid term roadmap.