The Big 6 leads the rest of the conference in literally every category:

SEC Football Championships
24- Alabama
13- Tennessee
12- Georgia
11- LSU
8- Auburn
8- Florida
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6- Ole Miss
2- Kentucky
1- Miss. State

All-time winning percentage:

71.55%- Alabama (#5 nationally)
68.03%- Tennessee (#10)
64.89%- LSU (#12)
64.79%- Georgia (#13)
63.02%- Auburn (#14)
62.87%- Florida (#16)
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60.18%- Texas A&M (#21)
58.93%- Arkansas (#28)
56.10%- Ole Miss (#46)
54.91%- Missouri (#54)

All-time standing in the AP (points):

964- Alabama (#3 nationally)
678- Tennessee (#9)
602- LSU (#11)
554- Auburn (#12)
548- Georgia (#13)
486- Florida (#17)
-----------------------
439- Arkansas (#18)
365- Texas A&M (#20)
331- Ole Miss (#23)
251- Missouri (#30)
118- S. Carolina (#57)
115- Miss. State (#58)
96- Kentucky (#63)

National Titles
*Awarded by AP or UPI/Coaches Polls

10- Alabama
3- Florida
3- LSU
2- Auburn
2- Tennessee
1- Georgia
1- Texas A&M

The Big 6 are so far out front in terms of overall accomplishments, membership in the club cannot be given out or removed due to what happens in a single year or even an entire decade.

Texas A&M or Ole Miss could go on a tear and possibly push it towards a "Big 7"... but it would likely take 10-15 years of Top 10 finishes, a National title or two... plus at least 4 or 5 SEC Titles. But again, it would take a minimum of 10-12 years of this type of winning before the conversation could really begin.

Elite status by nature is not quickly gained or lost. That's the entire point.