You said next 24 months. Just how many decades do you want for proper testing during a pandemic? I say almost 2.5 years can be enough. Some of the "new"vaccines have been in development for years, due to SARS.
Not to mention a large portion of the non-takers won't take it because they are anti-vaxxers, plain and simple.
And as I said, if the other 2/3 takes it the rest will still be protected up to a point. So yes, a working vaccine will make a huge difference. Don't worry, the Chinese will test it first, they are actually doing it already on their military.
And YOU assumed there will be a vaccine yet, in your next post you are assuming there will never be one. Pick one stand and stick with it.