It reads like a high-school assignment in which "100 years from now" is entirely used as a narrative device and the author with his literary skill set kind of seemed bored with it and wants to just get over with.
He basically mirrows the sentiment of his time by extrapolating - with hardly any spin of his own - the low hanging fruits: new rays, wireless technology, movies with sound & color, ease of housework (compressed papier mache: Ikea?), community dwellings, "servant problem", everything you need in a pill, city roofed with glass (his own spin?) ...
His view that 1822 (Jefferson) is more dissimilar to 1922 than 2022 will be to 1922 (for a little girl) is weirdly off. He does not go into detail as to why and in which fundamental ways.
"The more we discover the less is left" seems even more absurd and goes contrary to the open-endedness of the scientific inquiry (which he praised beforehand): "the more we discover the more questions arise".
Finally when turning to political issues his narrating device serves only to illuminate his own (political/societal) views: emanicaption of women (from 20.000 years of slavery), tendency for socializations (not socialism!), (unconscious) nationalizing of important industries, "Anti-Trust Acts" in which the State limits profits and arbitrages between industries and workers, international trade in the hands of "controlled combines" (globalization) as a pacifying force, political conditions (nations) as a driver for war. Well, as a witness to WWI, WWII surely had to be "horrible beyond my conception".
The potential of America to immense wealth ("most enterprising creature") away from a euro-centric (and partly his feminist views) are imho his most refreshing views.
As a necessary flattery for the reader he goes on to predict an american flowering in literature and arts ("infinitely more than they are producing today" sounds more like an insult by an Englishman ;)).
And by ending with "there will be no more things one can't say and things one can't think" and "a great liberalism of mind will prevail" I can only reply 100 years later with Goethe's 200 years old Wahlverwandschaften[1] and one prominent slogan of Occupy Wall Street: "None are more hopelessly enslaved than those who falsely believe they are free."
("Niemand ist mehr Sklave, als der sich für frei hält, ohne es zu sein")
[0]http://paperspast.natlib.govt.nz/newspapers/TS19260408.2.125...
[1]http://www.zeno.org/Literatur/M/Goethe,+Johann+Wolfgang/Roma...