I've read/ heard plenty who assume future variants will become milder. We also still don't know if Omicron is inherently "milder" (WHO disagree it should be classed as such) or the decreased severity/hospitalisation is due to the already existing immunity from vaccination and previous natural infection. This is because it is such a new variant and the data is ongoing. Immunity from both will wane over time,
Also, Covid is still a bigger killer than flu in terms of mortality and its knock on effects on society.
https://www.theguardian.com/world/2022/jan/11/uk-covid-death-toll-ons
At what point do we say it is now beneficial to be infected naturally so that each time we catch it it does become milder due to the level of immunity in our population. Because basically whether it is milder depends on our individual and general population's level of immunity. That question hasn't been asked as far as I know in a safe controlled way. For me that means no longer wearing an FFP2 mask in congregate indoor/outdoor settings.
Annual shots - yes a combined flu/Covid booster each winter would be my guess. But those not vulnerable may have to pay for this.