So you're drawing a straight line between two data points. What am I missing here?
You forget that large sections of the world are still fighting Delta. And new mutations are brewing from that.
And even if you get Omicron, that doesn't mean Delta stops circulating. Viruses don't play a winner-takes-all strategy in propagation between strains as if they are in direct competition. Delta arose from relatively weaker strains of Covid... so it's not impossible.
Well, my only worry was that Omicron doesn't give immunity vs Delta and other variants, but so far the data shows that luckily it does give immunity.
https://www.medrxiv.org/content/10.1101/2021.12.27.21268278v1
https://www.medrxiv.org/content/10.1101/2021.12.26.21268380v1
Second paper shows that previous infection with Delta and vaccination give immune protection vs Omicron. And most likely Omicron infection give immune protection vs Delta. The first paper shows that Omicron is displacing Delta in Denmark.
The problem with your logic is that Delta mutations must provide a new strain that is more transmissible than Omicron. This is basically impossible because Omicron is coming from another evolutionary strain of the Covid virus tree. It's multiple times more transmissible than the Delta variants. In a month or so Omicron will be the dominant variant all over the world and it will give immunity vs the other strains too. Not only that but it will suffocate the other variants.
Here's the evolutionary tree of Omicron.
As you can see it's completely different than the Alpha, Beta, Gamma and Delta. Only from the branch of Omicron could be another strain as infectious. And the new strain from the Omicron branch should also be more lethal and capable of evading the natural immunity from previous infections... It's next to impossible.