This may be subjective, but this concerns shows that were referenced a lot in pop culture, boomed big, and seemed to be watched by a lot of people at its respective peak.

Survivor was very influential throughout the early 00s and even into the later half of the decade, before falling off around 2010

ER is another show that was critically aclaimed throughout it's first ~10 seasons, before plummating in viewership the last few seasons.

Without hesitation, the 1970s would be All in the Family since it broke barriers for sitcoms by dealing with issues such as racism, menopause and rape.

Perhaps Julia in the '60s, but then again Laugh-in would rank high in this discussion. This based on cultural references not cross section popularity.

1990s Boy Meets World, 90210, The Simpsons, Beavis & Butthead, Married with Children, Power Rangers, Full House, Family Matters, Friends, Seinfeld

2000s Malcolm in the Middle, Sopranos, Chappelle's show, Punkd, The Osbournes, Family Guy, Jackass, Dawson's Creek, Smallville, One Tree Hill,
The OC, Dragon Ball Z

1950s:
1. I Love Lucy
2. Your Show of Shows (which seems to have become forgotten for some strange reason)

1960s:
1. Laugh-In
2. The Ed Sullivan Show
3. The Dick Van Dyke Show
4. The Twilight Zone
5. Star Trek

1970s:
1. All in the Family
2. Saturday Night Live
3. The Jeffersons
4. The Mary Tyler Moore Show

1980s:
1. The Cosby Show
2. Cheers
3. Miami Vice
4. Dallas

1990s:
1. The Simpsons
2. South Park
3. Seinfeld
4. Friends
5. The X-Files
6. ER

2000s:
1. The Sopranos
2. Mad Men
3. Lost

2010s:
1. Breaking Bad
2. The Walking Dead
3. Game of Thrones

10 Most Important TV Shows Of All Time (https://screenrant.com/most-important-tv-shows-all-time/)

The various technical, commercial and artistic breakthroughs that have led to the modern era of television can be credited to a handful of series.

1990s Boy Meets World, 90210, The Simpsons, Beavis & Butthead, Married with Children, Power Rangers, Full House, Family Matters, Friends, Seinfeld

2000s Malcolm in the Middle, Sopranos, Chappelle's show, Punkd, The Osbournes, Family Guy, Jackass, Dawson's Creek, Smallville, One Tree Hill,
The OC, Dragon Ball Z

Yeah, you got most of the big ones. I'd also add in Sailor Moon to the 90s, and DBZ to there too since it debuted in the US in the 90s. I think it also got popular back in '98 and '99.