The article has it slightly wrong, BTW. Boeing's SST did get off the drawing board. They had gone so far as to build an almost complete full-sized mockup.

The mockup was torn down and lost for quite a while, until someone came across it. The Hiller Aviation Museum at San Carlos Airport currently has the pieces and is rebuilding it.

I got to see it a year or two ago while the museum was in the process of restoring it (couldn't get in, but could walk around). I wonder if they've fiinshed it by now...?