In 1926 if you were privileged enough to get published you could write in an authoritative voice knowing that no-one would challenge you, or if they did it would take many months for any such challenge to appear. Perhaps a letter to a newspaper or something. These days anyone can publish anything at any time and if you write in that authoritative sort of style its just begging for someone to come in and contradict you (you see it in HN comments all the time).
Hence people write differently now
OR
And so I thusly declare that is a most elegant explanation, without possible rebuttal, for why this most elegant authoritative style is so rarely seen in these times.