Unfortunately a lot of R's internal standard library code isn't much better, rife with assumptions of minuscule data, gratuitous copying of input data many time

Unfortunately a lot of R's internal standard library code isn't much better, rife with assumptions of minuscule data, gratuitous copying of input data many times over and pointlessly returning them in results, glacial I/O, grossly inefficient implementations even at the C level, etc. Using R in a production environment is a slow journey through reimplementing R itself.