Wait, who are these people? WYSIWYG App builders have existed for decades and Excel still dominates. Maybe you don't agree, but the main reason for this in my opinion is because these app builders are way too complicated and learning them is largely pointless since their use cases are generally super trivial. Why build an app if Excel+Email works?
Further, if these things do start taking off I don't think the people using them will be non technical people, it will just be technical people shifting their job description.
It is like an all in one hammer, the craftsman throws it in the garbage, and the non craftsman has no idea what to do with it.