In South Africa they found that Omicron displaced Delta almost completely within 2 weeks, so making the supposition that Delta cases will remain at present level till Christmas ( or as they say zero growth from present level ) is just plain wrong. To match the steep growth of Omicron there will be an equally steep drop off of Delta. Vast majority of Omicron cases in SA hospitals did not even know they had covid, they went in for something else, but routine admissions testing picked up covid ( the people did not even have symptoms ) - only then did they become ' a hospitalised covid case' - which is a lot more scary than 'someone in hospital for a broken leg, who just happened to have a positive covid test but have no symptoms'...
Best to consider Omicron as 'natures free vaccine', with maybe less side effects than the vaccines up to now.
You have to be careful in making comparisons with South Africa.
The population is much younger.
The percentage of people vaccinated is much smaller.
Many have previously been infected with other variants.
Many of the older people have died from Covid and therefore been removed from the people left to be susceptible to omicron.
It would be great if omicron proves to be much less severe but it is known already that irt is much more transmissable.
If it is much less severe --Great
If it is less severe but much more transmissable the extra transmisabilty will more than make up for the lesser severity.
Until the scientists know how much less severe it is it would be stupid to open the floodgates.