Once the rate of infection is slower there is the possibility a vaccine will be developed fast enough to make a difference in the current pandemic, but that’s unlikely.
What is likely is that peak concurrent hospitalizations is lowered - once the hospitals are saturated you get an increase in fatalities for everything. Survival rates for many diseases are strongly tied to availability of treatment - even in the cases of diseases like Ebola.
It also provides time for improved treatment modes, reducing the amount of time in hospitals and the fatality rates for those there.
The core thing that people need to internalize is that these lockdowns are not designed to reduce the total number of cases.
They are there purely to try and reduce the total death toll.