What languages have changed the most since their creation?
JS? IIFEs and prototypes to modules and classes.
C++? Plain pointers to smart pointers.
There must be more dramatic examples.
A (slightly dramatic) history of Engelbert's vision for knowledge tools, his prototypes on early timesharing systems, and the transition to personal computers:
Apparently sqlite does not enforce foreign key integrity by default! That's incentive to use something else even for prototypes/small apps.
https://stackoverflow.com/q/15301643/509706
34 environments, 24 compilers and 9 interpreters: the story of Eve, how it grew from Light Table, how they researched, built prototypes, and pitched the reinvention of programming to investors.
Part 1: https://youtu.be/WT2CMS0MxJ0
Part 2:
https://youtu.be/ThjFFDwOXok