Comment by CPLX

This feels like a classic example of survivorship bias. Based on the nature of computing resources in the 1950's and academic culture in general, it's likely that all language/compiler projects of the era were planned deliberately and slowly. One of them survived.

So all projects that have "stood the test of time" for that length of time have that attribute. Also having that attribute are all the projects of that era that failed miserably.