Oh is that why they didn't know they wouldn't work?
Know they wouldn't work at what?
There are people, whose whole lives have been dedicated to tracking patterns and statistics, and monitoring the real-time data over the past two years.
The things we do know...
The vaccine was extremely effective against both serious outcomes, and transmission, against the original strain and Alpha.
The vaccine was still effective against serious outcomes, but less effective at preventing transmission, with Delta.
Beta and Mu showed mutations that indicated potential immune escape, but ended up being "non-competitive" against Delta so largely ended up being a "non-issue"
Titers scores start to drop between 4-8 months against the spike protein (however, that only pertains to antibodies...which are like the front-line troops against the virus, B-cell immunity - which is tougher to test for - could still very well be intact...but isn't as "swift" when it comes to fending off the virus if exposed)
Omicron appears to be mild for the overwhelming majority of people who contract it, and smaller studies using samples from people who've had a 3rd dose suggest that 3 doses seems to do a pretty good job of neutralizing it, as to where samples from 2-dose recipients seems to be less so.
So, do tell from your data. How many boosters before this pandemic is absolutely over? You didn't know it then and you don't know it now. Lets just wait and see, as the "data" and "stats" are all changing as we go.
It depends, how long are people going to keep trying to resist any and all mitigation and prevention measures?
That'd be like asking "how many more mitigation measures will we need to end the problem of sexually transmitted diseases so it's no longer a thing", that all depends on A) the willingness of people engaging in risky behavior to change their behavior, and B) how fast science can come up with medicinal solutions to the problem.
There is no option that includes both "I don't want to change my behavior" and "I don't want to embrace any medicinal solutions"
Same could be said of heart disease. If a person is developing heart disease from eating lousy food and being sedintary...their choices are A) change your diet and start exercising, or B) take blood pressure and cholesterol lowering medication. That's it... There's no "Option C" in which that person can continue to eat 4 eggs and 8 slices of bacon for breakfast, a bacon cheeseburger for lunch, and pizza for dinner and watch TV all day, and refuse to to take any of the approved medicines, and expect to solve their problem.
That's your choices with Covid.
Everyone on the planet stays home for 4-6 weeks and zero contact with anyone
Or, decide to live with it and accept it as another endemic disease, and use the appropriate pharmaceutical interventions in order to make it more manageable.