That isn't clear. A vaccine may be more than a year away. It implausible that any country can maintain a lockdown that long. When they open, Covid will likely resurge.
Sweden chose to pay up-front with a higher first-wave death count, and avoid some of the economic cost of locking down. Other countries will pay later with a higher second-wave death count, and pay a higher economic price.
Nonsense. Getting herd immunity by allowing controlled spread will take 5 to 10 years. Letting the virus spread uncontrolled will still take 3 years (the 1918 Spanish Flu pandemic lasted until 1920) and the death toll will be insane.
Any decent virus eradication strategy doesn't rely on indefinite lockdown. The most effective eradication tool is aggressive testing with contact tracing. Lockdowns are just a blunt instrument that can buy you enough time to ramp up testing and tracing capacity. South Korea, Taiwan and Vietnam have been testing and tracing since January and they never locked down. Contact tracing is also what allowed us to eradicate smallpox. We didn't need to shut down all of Africa and Asia or vaccinate 3 billion people to do that. Half of EU is coming out of lockdown now and switching to tracing instead. Only Sweden will stay in the weird not-really-locked-down-not-really-open-either limbo for a long time.
See also: Coronavirus: The Hammer and the Dance