agreed! a couple things seem to be holding this back:

- the academic publishing model incentivizes groups to build their own tools

- the small-ish market for something like this has kept commercial software from taking off (Genomatica started by building a tool like this in the early 2000s, before pivoting to bioprocess development)

- it's really hard to specify pathways in concrete physical terms. Even a chemical like glucose is actually a collection of pseudo-isomers (alpha & beta D-glucose). And try firmly defining a "gene" in your database!

that being said, there's a ton of work going on in this field and many cool projects to follow: https://dd-decaf.eu, https://biocyc.org, http://bigg.ucsd.edu, http://metanetx.org