DoorDash, Affirm, Roblox, Airbnb, C3.ai and Wish all filed to go public in recent days, which means some venture capitalists are having the best week of their lives. Tech companies that go public capture our imagination because they are literal happy endings. An Initial Public Offering is the promised land for startup pilgrims who may wander the desert for years seeking product-market fit. After all, the “I” in “ISO” stands for “incentive.” A flurry of new S-1s in a single week forced me to rearrange our editorial calendar, but I…