Brian Halligan has a line he uses in his MIT scaling course that should make every early-stage founder uncomfortable: "Starting a company has never been easier. Scaling one into a durable, high-impact organization has never been harder."

He's not being dramatic. He's describing a structural shift that most founders are sleepwalking through. In a recent conversation on Lenny Rachitsky's podcast, Halligan — who co-founded HubSpot, ran it for nearly 20 years, and now coaches Sequoia's fastest-growing CEOs — laid out exactly why the startup era we're entering will produce more companies and fewer winners than ever before.

The founders who understand this will build differently. The ones who don't will mistake early traction for a growth engine and wonder why the wheels came off at Series A.