Doesn't that require Istio and a few other things as well? I wouldn't wish Istio configuration and maintenance on anyone but the larger shops/teams. You might not be technically locked in, but not everyone can afford to dedicate the attention to tuning and maintaining Istio.
Source: at mid-sized company who has Istio in the stack.
Knative just needs a gateway (LB); not a full mesh. Istio is the default option. Alternatively you can use Gloo, Ambassador or something specifically built for Knative such as Kourier.
Source: at mid-sized company who has Istio in the stack.