Miller is implying here that people are too taken up with materialistic concerns. Howard is completely wrapped up in the tape recorder, the exciting new gadget that he's just acquired, and expects Willy to share in his excitement. It takes him several minutes to even ask why Willy has come to see him. Willy is in desperate need of help, but Howard has no time for him, only for the new tape recorder.
Miller seems to be suggesting that modern society favours the development of new technology at the expense of human lives. A socially successful man like Howard eagerly embraces this technology, but the ageing Willy, who's been left by the wayside, is continually frustrated by gadgets like the car and fridge which he continually refers to throughout the play and which are always breaking down and running up huge bills. In fact, Willy even appears frightened by the tape recorder at one point, when he accidentally turns it on and doesn't know how to turn it off again.