The Fifty Greatest Breakthroughs?

The Atlantic's list of the "50 Greatest Breakthroughs Since the Wheel," produced by a team of technology scholars: 

1. The printing press, 1430s
2. Electricity, late 19th century
3. Penicillin, 1928
4. Semiconductor electronics, mid-20th century
5. Optical lenses, 13th century
6. Paper, second century
7. The internal combustion engine, late 19th century
8. Vaccination, 1796
9. The Internet, 1960s
10. The steam engine, 1712
11. Nitrogen fixation, 1918
12. Sanitation systems, mid-19th century
13. Refrigeration, 1850s
14. Gunpowder, 10th century
15. The airplane, 1903
16. The personal computer, 1970s
17. The compass, 12th century
18. The automobile, late 19th century
19. Industrial steelmaking, 1850s
20. The pill, 1960
21. Nuclear fission, 1939
22. The green revolution, mid-20th century
23. The sextant, 1757
24. The telephone, 1876
25. Alphabetization, first millennium b.c.
26. The telegraph, 1837
27. The mechanized clock, 15th century
28. Radio, 1906
29. Photography, early 19th century
30. The moldboard plow, 18th century
31. Archimedes’ screw, third century b.c.
32. The cotton gin, 1793
33. Pasteurization, 1863
34. The Gregorian calendar, 1582
35. Oil refining, mid-19th century
36. The steam turbine, 1884
37. Cement, first millennium b.c.
38. Scientific plant breeding, 1920s
39. Oil drilling, 1859
40. The sailboat, fourth millennium b.c.
41. Rocketry, 1926
42. Paper money, 11th century
43. The abacus, third millennium b.c.
44. Air-conditioning, 1902
45. Television, early 20th century
46. Anesthesia, 1846
47. The nail, second millennium b.c.
48. The lever, third millennium b.c.
49. The assembly line, 1913
50. The combine harvester, 1930s

Pretty good list, but what's with the Gregorian Calendar? Much of the world gets on fine without it. And while 19th-century sanitary systems were really important, they weren't any better than some of the systems built by the Romans.

Missing are any of the technologies that transformed the production of cloth and clothing -- the water frame, the power loom, the sewing machine. Remember that for most of history most people had one suit of clothes. And without mechanical spinning and weaving, the cotton gin would not have amounted to much.

And what about plastic?