Yes, though I'd like to point out that "scale to zero" is a loose definition to mean anything that can be transparently scaled to 0 whenever an app/service is idle, and then wake up when traffic to the service arrives once again.
The problem in practice with Cloud Run (and similar products from other providers) is that it can take seconds or minutes for the platform to detect idleness, during which you're still paying, and then seconds to wake up -- during which users/clients have to wait for a response or possibly leave the service/site.
For my taste, real scale to 0 would be: detection and scale to 0 within < 1 second of a idleness, and wakeup within an RTT, such that the mechanism is transparent to end users.
As a shameless plug, this is what we do at kraft.cloud (based on years or research, LF OSS work, unikernels, a custom controller and overall non-negligible engineering effort).
The problem in practice with Cloud Run (and similar products from other providers) is that it can take seconds or minutes for the platform to detect idleness, during which you're still paying, and then seconds to wake up -- during which users/clients have to wait for a response or possibly leave the service/site.
For my taste, real scale to 0 would be: detection and scale to 0 within < 1 second of a idleness, and wakeup within an RTT, such that the mechanism is transparent to end users.
As a shameless plug, this is what we do at kraft.cloud (based on years or research, LF OSS work, unikernels, a custom controller and overall non-negligible engineering effort).