Heaven help us all, they’re doing it again. The “who” are the venture capitalists, and the “what” is super-inflating another start-up company bubble. Consider the following valuations, as summarized by Steven Davidoff-Solomon in this morning’s New York Times: Instacart, a same-day grocery delivery service (remember WebVan?) wants to raise $100 million at a $2 billion valuation. Too modest? How about WeWork Companies (why not share your office space the way Uber shares cars?), which closed on $355 million at a $5 billion valuation. And then, of course, there’s Uber, with a $41 billion valuation, but only a modest share of the $7 billion a year people spend on cabs.