Not having any lockdown - not putting into place any measures to reduce infection - would have resulted in hundreds of thousands of deaths. That in of itself would have severe economic consequences, to say nothing of the very real personal costs which would likely touch almost everyone in this country. Furthermore, it's becoming clear that many people take months to recover and many more suffer permanent lung damage. How much do think it would cost the economy, and the NHS, to support possibly hundreds of thousands of permanently damaged invalids?
Add to this that people will stop going to pubs, cinemas, shops, restaurants, work once it becomes clear that the death rate is spiralling out of control (an effect that could already be observed the week before the lockdown was implemented). This also has an economic effect. Not attempting to control the spread of this disease has economic consequences which are likely to be as severe as the lockdown.
Indeed, this is the point most seem to miss, that while the deaths are bad and would have been worse, the numbers of sick that would result from no protective measures at all would be overwhelming for the healthcare services and have severe knock-on effects for those with other ailments needing treatment. It isn't like 'flu where Bob in Accounts would take a week and then be back, he could be gone for 2 - 4 weeks or more and still have issues afterwards. His month out of action is bad for his employer and ergo the economy. Multiply that exponentially by all those who don't die but need time to recover and the economy potentially would be worse off than it is! At least under lockdown some business could continue and cogs could turn. This is what is not understood and why the World's Leaders have taken this so seriously. Collapse Healthcare and combine that with a large number of off sick and the country would be in dire trouble. It's short-term pain vs long-term pain. There is no pleasant choice.
I fear Brazil and parts of the USA are going to demonstrate just what happens when Leaders decide to ignore the virus. Until a cure is found, we have to learn to live with this and adapt to rolling control measures. Here in the Algarve region of Portugal, we have an excellent record so far, just over 500 known infected and 15 deaths. Amazing really, but the locals took this very seriously early. Masks, social distancing etc.
However, a group of youngsters decided to have a large party recently and within days, 76 new infections all from that party. The virus is living amongst us. It is ready to spread like wildfire. We have to keep a lid on it or risk huge harm to our society. The young unaffected? They can and do die from this, albeit at far less risk but they too can get badly ill and that in itself is not pleasant. It is a numbers game and it actually doesn't take massive numbers to create major disruptions and result in tragic costs. Flippancy over percentage amounts sadly only turns into real numbers when directly affected for many.