Silicon Valley VCs have a new obsession that perfectly captures the grave danger facing startups : How long is your 'runway'?

· As the coronavirus-led economic shutdown drags on, many investors have started counseling startups to have more than a years' worth of "runway" to avoid having to raise funding on poor terms.
· But VCs are split on how much startups should be socking away. Some have estimated 18 months oof reserves could suffice, while...