Judging that aside,
And with that, IBO officially joins Stardust Memory as the only Gundam show where the baddie actually wins and with such a huge amount of characters that died, it might even have surpassed Victory Gundam in death counts. Hopefully the next Gundam series would be an improvement over IBO.
And unlike Stardust Memory, IBO isn't an origins or prelude story to anything, where the bad guys winning is simply due to them needing to survive for the next show's plot. So nobody here saw Rustal's total victory coming, really.
Ultimately, I'd like to think of the ending of IBO as a satire of the 'Small Heroic Resistance Group stands up to Large Big Bad Entity and Proves the Justice of their Culture' formula that Zeta Gundam popularized, and which almost every other non-OYW, non-BF Gundam show (F91, V, Wing, X, SEED, SEED Destiny, 00, AGE, G-Reco, etc.) tended to follow on since Zeta. In a more favorable setting, in fact, Tekkadan basically would be
the AEUG --- and like the AEUG, they wouldn't have solved anything either had they won because Tekkadan's schtick basically consisted of the same 'brute force and just destroy the enemy in front of us, and let everything sort itself out afterwards' methodology that $insert_small_heroic_resistance_group also followed since the AEUG popularized the trope. IBO's message IMO is that this just doesn't work in reality, full stop.
In Zeta, the AEUG beat the Titans, but like Tekkadan they had been so focused on fighting and simply destroying their enemy (and following the notion that if the Titans were destroyed all would be automatically well with the Earth Federation) that once the war WAS over they didn't have any actual substantial idea on how to reform the Earth Federation, had the power to do so, or even had stopped to think that the REAL problem with the Earth Federation really lay within its own bureaucracy rather than with just some extreme rebel faction - and as a result there was peace but the status quo then set right back in, causing more people to become increasingly disillusioned (Char, Hathaway, etc.) and start more wars to try to find an answer.
Had Tekkadan won as per Gundam norms, would they have had changed a thing? Not really IMO. Rustal, McGillis and Gjallarhorn were demolished but from there, I don't think Tekkadan would've had an idea on how they had to follow through on what they had won, especially without Orga, and there would be peace for awhile before Tekkadan and Mars fell back to the same patterns as before - which is exactly why the UC was such a clusterf*ck of 70+ years of running conflicts followed in between by short periods of peace (that only lasted as long as some other disillusioned nutcase didn't decide to step up and try to change things). Ultimately, IBO's message IMO is that the 'destroy all opposition and then sort things out later' approach to most Gundam shows seldom works in real life, or even in reality; the 'heroic resistance' winning doesn't necessarily solve all problems, either (and in fact might end up causing more problems than they solve in the long run).