GalacticStorm
Smart Alec Know-It-All
First off stop speculating. You dont know Thanos absorbed the entire race of Celestials. That point was neither stated or depicted on panel.
The handful of cosmics and heroes Thanos beat down believe it or not account for a minute percentage of all powers and civilizations within the universe. I think thats safe to assume Mr Master.
So Thanos saying "others might be equally foolish" and him continuing to absorb all that might threaten his reign could quite feasibly be referring to the rest of the universe and NOT the rest of the multiverse as you have unjustifiably asserted
Either way in the very same issue just a few pages later Adam Warlock appears and THANOS refers to how he destroyed just a universe:
“Only you could miss the end of the UNIVERSE”
“That is how the UNIVERSE came to an end”
At the end of that same issue:
“I can sense the UNIVERSE resuming its full glory and scope”
(I take it Thanos decided to ignore the rest of the multiverse he apparently destroyed at some point off panel)
In Thanos own title that came after “The End” it was stated many a time by Thanos on separate occasions that he destroyed and recreated just the UNIVERSE
Thanos #1:
“The first day of my reign ended with me destroying the entire UNIVERSE”
“The mantle of supremacy was tossed aside. The UNIVERSE was resurrected with no memory of its demise”
Thanos#2
“I even happened upon Thanos during his brief stint as THIS ACTUALITYS supreme being and witnessed him forsake that might to right a perilous imbalance in the UNIVERSE”
Going by LT’s bio and multiple issues where the debated point is stated by both Adam Warlock and THANOS ON PANEL, Thanos destroyed and recreated just a universe as can be interpreted from the art and as stated point blank in the issue it happened in.