In an answer to the question Tools for the Langlands Program?, Emerton, in his usual illuminating manner, remarks on the reciprocity aspect of Langlands Program: "...As to constructing Galois representations attached to automorphic forms, here the idea is to use Shimura varieties, and one can hope that, with the fundamental lemma now proved, one will be able to get a pretty comprehensive description of the Galois representations that appear in the cohomology of Shimura varieties..."
Ten years after the remark was made it seems worth asking: to what extent has the hope been realized? Do we now a clear delineation and comprehensive description of Galois representations coming from Shimura varieties?
Furthermore, how do constructions of Galois representations attached to torsion classes in the cohomology of arithmetic groups by Scholze et al. in the same period relate to another part of his response, " ...Since Shimura varieties are currently the only game in town for passing from automorphic forms to Galois representations, people are thinking a lot about how to move from any given context to a Shimura variety context, by applying functoriality ..."?
