What is TPK?

A made-up algorithm (named after the authors) that's designed to exercise a general set of operations.


Where did the term “compiler” come from?

Grace Hopper used it first, to mean a took that automatically stitched together pre-complied libraries of code to build a complete program.


Why were higher-level languages/systems not embraced more enthusiastically at the time?

A combination of factors, several of the most important of which were that translating expressions into machine code wasn't really the "hard part", machines were too small and slow to handle ambitious compilers/interpreters, and the performance of these systems left much to be desired.


How do the languages/systems in the paper compare to the languages in common use today?

Most are completely different.  Some, like flow charts, were never intended to be compiled into runnable code, many of the others were "incomplete" -- lacking conditionals or output.  FORTRAN was one of the few that starts to look modern, as does ALGOL, though it's outside the range covered by the paper.