Yes there is we know that diseases can be eradicated by achieving a level of vaccination. Polio etc. It is novel to a degree but has severely closely related viruses. The issue is probably more the unpredictability of human nature!
Sweden because they are getting on with their lives in a better manner and probably causing less damage to their economy which will recover quicker and cause less harm to the country in the future. 900 or 2000 deaths out of 10 million do the maths its still a small percentage of the population and Portugal will no doubt get another spike in deaths at a later date as less people have been exposed to this virus. But who really knows? Not me.
www.stokesentinel.co.uk
If we accept the R value originally was 2.5, no one had immunity from previously being infected and each infected person on average infected 2.5 others... it would be a reasonable assumption that once 50% have been infected, and assuming infection results in immunity, then all else being equal the R value would be cut in half to 1.25, insufficient to wipe out the Virus. Of course we now have measures that have reduced the R value. The more effective these social distancing measures are at minimising the R value the lower the level at which we will start to benefit from herd immunity.
The people with the most disposable income are the 'grey' pound, even my daughter who sells in a young area, her customers are over fourty. So to get the economy moving in all the retail and hospitality industry, you have to give your customers security that they are not going to become infected. Older people tend to shop local, buy or eat out on a regular basis and spend a bit more. The 'spoons used to be full of people in a morning, you couldn't get a seat hardly at lunch, of the over 50's and older. They would also do their shopping in local shops.
Love it. I am quite capable of spending from home. Its a bit like a EHO food hygeine rating, who would you rather buy from or work with? Someone who cares about their customer and staff health or like the big processing hogg plant in the US, not give a dam.
If you are worried then obviously you should stay at home but the truth be told you may be sitting at home a long time. The rest of us well we need to try and get back to as close to normal as is possible and as soon as possible and while you say older people have a greater disposable income they also cost the country quite a lot to look after as well.
Got to ask - are you really an oil baron?
I am not sure what you mean about costing the country a lot of money. If they have it they are still spending and paying tax on everything they buy and still paying tax on pensions if its big enough. If you look at older people they often cost the NHS the most in the last two years of life. Younger, usually sicker people cost the NHS more for longer, the disabled child that would have died 40 years ago, will now live until they are 50, with NHS and socail care support. They get more social funding than the old for care homes.