A subversive thought: as it becomes cheaper & cheaper to build start-ups, prices would fall too. Granted, start-ups are not interchangeable commodities, but given that so many are being created, that ought to impact pricing (aka valuations). Asymptotically, this could lead to a start-up being valued "at cost" (or below it in a serious downturn).
As I said, just a subversive thought. I am sure it doesn't apply to any of us here ;-)