There’s no public knowledge of his intentions. However Gabe speaks on how Valve operates plenty and in general, if the industry is doing one thing, they often explore doing the complete opposite.

Valve’s primary thesis is exceptionally talented people are most productive when they don’t need to think about money, are surrounded by other exceptionally talented people, and there’s minimal people telling those people what to do.

I doubt Gabe would want the soul of Valve to die with him so his succession plan will factor that in.