From the article:

> One of the first technical considerations of the modern fire escape was carried out by the Franklin Institute in 1881 after the Randolph Street mill fire in Philadelphia trapped 35 people inside. Their conclusion was that external egress paths, in other words, the bolt-on fire escapes had, quote, “comparatively little value.” They recognized the fact that it was the only practical choice in some situations, but that internal stairways, properly constructed, afforded the best means of escape.

I took "The recognized the fact that it was the only practical choice in some situations" as a much less general statement than

> External fire escapes are the best they could do 150 years ago