Pittsburgh need not look west towards Silicon Valley. The engine driving the Knowledge Economy in this part of the world surrounds Washington, DC. Despite the mobility of the knowledge labor market, this geography is unlikely to change.
Knowledge workers tend to bounce between a small numbers of places. For the most part, these locations are already determined. In terms of the Burgh Diaspora, where the top-end talent will go is predictable. A significant number of them will travel no further than the DC region. Furthermore, Pittsburgh itself is already locked in as a nexus for scientists and engineers.
The key variable in the study linked above is federal funding. Follow the pork and find the counties with the most scientists and engineers per capita. Venture capital can chase ideas wherever they go, but subsidies mitigate risk. Tapping into this treasure trove of public investment is worth the effort. However, government labs are unlikely to move. Instead, the best and brightest will relocate to where these jobs are currently located. This is true for every region, not just Pittsburgh.