Upzoning might seem like an obvious preference for tech companies and sometimes they act on this preference. It's useful to remember, though, that they have countervailing short-term preferences for single-family zoning.

Tech companies themselves have many internal constituencies (managers, line programmers, service workers). Since these companies are extremely not democracies, it's very easy for the preferences of a small valuable constituency (executives and managers) to override the preferences of a larger commoditized constituency (new grad engineers and janitors). Valuable internal constituencies are already compensated enough to buy a single-family home and generally don't want density.

It would be difficult for e.g. Facebook to publicly support upzoning in Menlo Park when half the NIMBYs in the room are relatively valuable mid-level engineering managers at Facebook. So we don't see these tech companies in general putting big resources behind really transformative upzoning projects.