I don't think anyone expects nvidia to "sink". We're concerned that competitive pressures and possible reductions from sky-high demand could make it really hard for nv to justify or maintain their current valuation.

That is, revenues may be unusually cyclically high.

It's going to be hard for frontier labs to keep spending at this rate without starting to make money. And even if they do, lower cost alternatives will likely impact at least to -some- extent how much of that revenue nv gets.