You seem to be assuming that the message was “if you understand what is going on, you will choose to build your own silicon”—if so, then, yes, it overlooks threshold resource needs to do that.
OTOH, the intended message could be “you can't fully understand the issues without the insight gained by building your own silicon”, in which case it would be just as true of companies without the resources to build their own silicon.
Security is about managing risks in a world where resources are limited.
Building your own silicon is the last thing you do to ensure security even if you are Google, you only do that when it’s the last broad viable attack vector left for your adversaries to exploit.
OTOH, the intended message could be “you can't fully understand the issues without the insight gained by building your own silicon”, in which case it would be just as true of companies without the resources to build their own silicon.