Those accessible programming environments tended to exhibit exponentially worsening performance and maintainability characteristics as the complexity of the system being built with them grew.

This would be have been fine, so long as these systems remained relatively simple, and were rebuilt in more heavyweight but scalable languages once they reached a certain level of complexity. But that isn't what happened. Instead, they just kept growing into twisted, unmaintainable monsters that organisations were completely reliant upon, but which were an absolute nightmare to maintain and extend.

As a result, the industry shifted to encouraging the use of "real" programming languages for everything, even the simplest systems, because the greater up-front costs were saved many times over by having a sane story for long-term maintenance and improvement.