This is The Higher Things by J. R. Pierce. I found it in the anthology Nova 1 edited by Harry Harrison.
The scientist is Haskel van Manderpootz (Pierce was an engineer and I would guess this was a tribute to Weinbaum - effectively a fanfic). He has abandoned the technical approach in favour of genetic engineering because he feels the technical approach is too limited. He does indeed engineer a shrub that grows into a chair:
He produced a fine, bushy growth which trained itself in the form of an armchair, and had only to be cut and dried to be of service (he still used one of these; it was remarkably comfortable, although a little asymmetrical).
He uses his subjunctivisor (see the Weinbaum stories) to look into the future and see what effect his inventions have:
Despite all of his certainty that he was about to change the face of the earth and the habits of the human race, van Manderpootz was impatient to know the result. So, with one last fling at the mechanical, he revised his subjunctivisor to give a telepathic view of the truly far future.
Mankind doesn't go extinct, but retreats from the real world into virtual reality:
Man had found a way to live without effort, in the partnership with some simple organism, his body cradled and fed and kept young through the ages. And he had found telepathy as well. Finally, the very last man to walk the face of the earth had lowered himself into a tank and closed the lid. And men had lived in a world of dreams, thinking their thoughts together. They had forgotten their bodies, which lay on the face of the earth.