Creative tech start-ups face a daunting task in expanding to scale, Walter Isaacson said on Monday.
That poses a bigger challenge to the sector than a private funding bubble some prominent investors recently decried, the Aspen Institute CEO contended.
"I think the other conversation here is not that we're in a bubble. But we have a lot of start-ups. How do we accelerate them? How do we make them scale?" Isaacson told CNBC's "Squawk Alley" from the South by Southwest conference in Austin, Texas.
On Sunday, investor Bill Gurley told conference attendees that a run of huge private tech valuations could soon end, adding that venture capital firms have "no fear." His assertions follow investor Mark Cuban's recent claims that a private bubble exists worse than the tech stock bubble that burst in 2000.