This sounds off to me. Even if the CEO isn't a technical engineer literally working on the code, they are ultimately accountable for getting engineers and designers to build the right product. Building the right product is massively hard. Usually, it takes several wrong takes to get it right. 90% of startups fail.
When an engineer is hired post-traction, they may not see all the scars and dead bodies of those failed attempts. It may seem easy to manage if the product is already a hit, because when there is true PMF it's hard to mess up.
But that's like those stories about how the military in WW2 thought they should be adding armor to the areas of the plane that had holes after sorties. That was totally wrong; the real problem would have been to add the armor to the areas of the plane without holes, because *those planes crashed and were never recovered.* In other words, what "seems easy to sit on the hands" is survivorship bias, and ignores the brutal reality of struggle that any founder will be able to relate with. Assuming that "engineers could run these businesses themselves" indicates a very incomplete understanding of what is involved with actually building and running a business.