I think that's a reasonable way to look at it.

It's not the route I'd take, after all, the video tag in html supports specifying multiple sources (including different formats/encodings), and with full control of the stack (they vend Safari) you could have logic on devices without AV1 hardware that prefers the AVC/HEVC/VP9 sources instead — then fallback to AV1 SW if it's the only option. That seems a better user experience than just failing to display content.