Theme: And this too shall pass - PASS can be added to the last word.
16A. Without a care in the world: FANCY FREE. Free Pass.
23A. Clove crusher: GARLIC PRESS. Press Pass.
37A. Big band venue: DANCE HALL. Hall Pass.
56A. Deceptive measure: SMOKE SCREEN. Screen Pass. (football)
64A. Log-on needs ... and, literally, what the ends of 16-, 23-, 37- and 56-Across can be: PASSWORDS
Argyle here. And this too shall be easier than Monday, eh? Fourteen 7-letter words makes this puzzle stand out.
Across:
1. Skatepark feature: RAMP
5. Tuxedo part: VEST
9. Flew the coop: LEFT
13. Old Voice of America overseer: Abbr.: USIA. (United States Information Agency)
14. Dislike intensely: HATE
15. Twisted shape: HELIX
18. Olympics segment: EVENT
19. Dipped chip: FRITO
20. Vatican City is one: ENCLAVE
22. Sweetie, in dialect: LUV
27. She, in São Paulo: ELA. (Portuguese)
28. "I think," in chats: IMO. (in my opinion)
29. Pointy hat wearer: ELF
30. CIA relative: NSA. (No Such Agency)
31. Prefix meaning "ten": DECA
33. Fictional visitors from space: ETs
35. Surprise victory: UPSET
41. U.S.-Canada defense system: NORAD. (North American Aerospace Defense Command)
44. Quite a long while: EON
45. Buckwheat noodle of Japan: SOBA
49. Tuna at a sushi bar: AHI
50. Okinawa okay: HAI. This concludes our trip to the Far East.
53. Fr. holy woman: STE. (Saint)
55. Hi-__ image: RES. resolution
59. Courtroom VIPs: DAs. (District Attorney)
60. Frozen convenience store offering: SLURPEE. Nationwide?
61. Funny Cheri: OTERI
63. Solitary: ALONE
67. Gung-ho, as a fan: RABID
68. Cuatro y cuatro: OCHO. 4+4=8 (Spanish)
69. __ Cong: VIET
70. Rare bills: TWOs
71. "That was a close one!": "PHEW!"
72. Odds partner: ENDS
Down:
1. Like some tuxedo shirts: RUFFLED
2. Usually: AS A RULE
3. Hand-held cleaner, briefly: MINI-VAC
4. Summit-ending agreement: PACT
5. TV channels 2 to 13: VHF. (Very high frequency)
6. Place for a ring: EAR
7. Iron alloy: STEEL
8. Like the bikini in a 1960 #1 hit: TEENIE
9. Burton of "Roots": LEVAR. What's he upto now? IMDb
10. Gridiron squads: ELEVENS. And Seven-Elevens are where you will find Slurpees.
11. Delicate handling: FINESSE
12. Extension on an unformatted document file: .TXT (text/plain)
15. Of assistance: HELPFUL
17. It's said that he said, "I never said most of the things I said": YOGI Berra
21. 25% of M: CCL. 1000x25%=250
24. "Absolutely!": "AMEN!"
25. Campus mil. group: ROTC. (Reserve Officers' Training Corps)
26. Won at musical chairs: SAT
32. Toothpaste-endorsing gp.: ADA. (American Dental Association)
34. "__ what I mean?": SEE
36. Start of a sequence ending in "thx": PLS. Please/Thank You
38. Stuck (to): ADHERED
39. Watering aid: HOSE
40. Feed the kitty: ANTE
41. "Stillmatic" rapper: NAS
42. Eponymous electrical current principle: OHM'S LAW
43. 1970 John Wayne film: "RIO LOBO" Oops! This clip is from the 1959 Rio Bravo. It is a much better movie so I'll leave it.
Clip from Rio Lobo below.
46. Call for pizza, say: ORDER IN
47. Like Dumbledore and Santa Claus: BEARDED
48. Lends a hand: ASSISTS
51. Nile snake: ASP
52. Summer treat: ICE POP. From your freezer, not a store.
54. It used to be plenty: ENOW. Enough.
57. Actress Mila: KUNIS. IMDb
58. Arrive at: REACH
62. "Slithy" thing in "Jabberwocky": TOVE
63. Works at a museum: ART
65. One called Miss: SHE
66. Sty mother: SOW. Miss Piggy?
Argyle