We don't know what will be popular 80 years from now, so my rough call on what was a "major" introduction is based on how great it was at the time and compared to new products since then. So there are several discontinued brands, including some of the greatest I tasted as a kid, Bar None and PB Max (a hit seller, but cancelled because the Mars brothers were afraid of peanut butter products).
Here is a chart showing these major national candy releases over time, where each chunk of time is the first or second half of a decade, marked by the mid-year:
|Whatchamacallit||Nestle Alpine||Bar None||Hershey C&C|
|Lemonheads||Starburst||Special Dark||Pop Rocks||Gummi bears||Airheads||Dove bar|
|Now & Later||Swedish Fish||Blow Pops||Bubble Yum||Nerds||Sour Patch||PB Max||Take 5|
It's the same picture as before, where innovation tracks the violence rate. Creativity gets off to a start in the '60s and early '70s, though Rolo and Starburst are the only huge hits. There's a peak from the later '70s through the first half of the '80s, and still a good showing through the later '80s and early '90s, including the PB Max (1990) and Dove chocolate bar (1992).
After the crime rate starts falling after 1992, there are only three candy bars worth noting, two very soon after from 1994 (Nutrageous and Hershey's Cookies n Creme), and one from 2004 (Take 5). We saw that in the earlier 20th C, where after the homicide rate peaked in 1933, there were a few major candy bars that came out shortly after in the mid-late '30s, but only one more during the entire 1940s.
Again the use of candy as an example seems silly, but it goes to show that cultural creativity tends not to be confined to just one domain. There's a wider zeitgeist of inventiveness or stagnation. The peak from roughly 1976 through '84, plus a lower but still highish point in the late '80s and early '90s, showed up for instance in popular music, movies, and cars. And that episode appears to be part of a broader pattern where the second half of a rising-crime period is the most creative phase of the cycle.