Part of the reason perhaps that previous diseases have taken so long to eradicate, despite the presence of vaccine, is the lack of political will and a lack of global coordination. A good example would be smallpox -- in theory, at least, we had the potential to eradicate that disease as far back as the 19th Century (which is, not incidentally, when the world "anti-vax" first reared its ugly head), but despite some, fairly strenuous, efforts in a few countries, it wasn't until the 1950s that a real global drive to eliminate the disease came around.
It may be mindless optimism in this case, but I still believe that it will be possible to bring Covid under control, albeit only if Governments and their citizens are prepared to work together. In practice that makes total victory extremely unlikely, but in theory at least it's better than admitting defeat, accepting a +20% or more rise in deaths, and accepting the expense of vastly expanding the healthcare system to cope with vastly increased short- and long-term care capacity.
We should probably consider doing the latter anyway, but in the meantime, it should be clear that Covid if left unchecked is devastating, and that's motivation enough to redouble our efforts to control the disease as far as possible.