I think this misses an important distinction. The issue here isn't the extent to which Congress can delegate rule-making authority to executive agencies. Those bounds haven't been moved. The issue is how how much deference courts are to give agencies when deciding when an agency-made rule reasonably adheres to the purpose and function of a statute. In theory the degree of deference shouldn't matter--agencies' retain the same rule-making authority and flexibility as before--but as a matter of process it absolutely does.
SCOTUS invented the Chevron doctrine because it believed at the time courts were too quick to second-guess the logic behind agency rule making, and in doing so unnecessarily and improperly inserting themselves into technical debates as well as broader political debates. IOW, the court was primarily concerned with people using the courts to subvert executive prerogatives and electoral politics. The concern now, apparently, is that administrations are using agency flexibility to subvert electoral politics.
Then and now, by moving the threshold for when courts can second-guess federal agencies, it's effectively altering the rights and responsibilities between Congress and the President, as well as between those two institutions and the electorate more broadly.
SCOTUS invented the Chevron doctrine because it believed at the time courts were too quick to second-guess the logic behind agency rule making, and in doing so unnecessarily and improperly inserting themselves into technical debates as well as broader political debates. IOW, the court was primarily concerned with people using the courts to subvert executive prerogatives and electoral politics. The concern now, apparently, is that administrations are using agency flexibility to subvert electoral politics.
Then and now, by moving the threshold for when courts can second-guess federal agencies, it's effectively altering the rights and responsibilities between Congress and the President, as well as between those two institutions and the electorate more broadly.