This was tried before, in the "expert systems" of the 1980s. Prolog and various 'production system' languages (e.g. OPS5) would decouple facts/rules from the execution engine. Then "just add" domain knowledge ...
As far as I can tell, what killed that was the unfeasibility of debugging. One bad item (or the lack of a critical true one) could poison the well, and good luck tracking it down.
The care and feeding of proper 'fact databases' remains expensive, and Google doesn't seem disposed to go there, apart from unit and currency conversions. (Add a 'hmm' for automated translation.)
So, this leaves two ideas for 'Alpha' as a product: a) they believe the database grooming expense can be profitable on a global web scale; b) they automated enough of the database grooming to make it profitable.