When was that part of SV culture? Even if you go back to the old-school SV firms, they were pretty negative on telecommuting, and ran regular offices. What era and kind of company do you have in mind? If you go back to the '60s-'90s even, Silicon Valley companies like Intel, Sun, Apple, SGI, Oracle, etc. required regular office time. You could certainly shift your schedule at many of them (e.g. come in at 10am, not 8am, as long as you stay late too), but you couldn't work from home, or get away with less than 40+ hours in the office (often 50+).