Illustration: Mica Warren

Daredevil Startups Are Finally Exposed for What They Are

Why the flimsy business models of Uber, Airbnb, and ClassPass are starting to crack under pressure.

Giuseppe Badalamenti, a pizzeria consultant outside Chicago, was flipping through the invoices of a particularly troubled client when a March statement from Grubhub, the food order-and-delivery app, made…