The issue is that the 'B' is not very consequential.

Consider something like Shopify - someone with zero knowledge of programming can wow you with an incredible ecommerce site built through Shopify. It's probably like a 1000x efficiency improvement versus building one from scratch (or even using the popular lowcode tools of the era like Magento and Drupal). But it won't help you build Amazon.com, or even Nike.com. It won't even get you part of the way there.

And LLMs, while more general/expressive than Shopify, are inferior to Shopify at doing what Shopify does i.e. you're still better off using Shopify instead of trying to vibe-code an e-commerce website. I would say the same line of thinking extends to general software engineering.