Reproduction is an exponential function. A small change in R has a large effect in rate of spread.

> We don't have a practical way to reduce it below 1.

First, this is just not true. Even the (likely pessimistic) Israeli data indicates that vaccinations reduce chance of infection by over 60%. This cuts R in half from 5-7 to 2-3, and probably less when you consider the window of infection is shorter for breakthrough cases.

Combined with other measures--contact tracing, masks, social distancing, improved ventilation, etc--the measures that got Alpha transmission below 1 without a vaccine would be effective with Delta in vaccinated populations. This could allow moving to a model of managing hotspots rather than dealing with unsourced community spread.

Second, you presume that there will never be a vaccine effective against Delta. I'd rather we do what we can now--which means driving of vaccination rates as high as possible as quickly as possible--to slow spread and buy time for targeted boosters to come out than to throw up my hands and just assume that everyone is gonna get COVID so we might as well just give up and stop trying.

Life is way to short and we can’t just piss it away being myopically focused on slowing exactly one very specific illness. Sorry.