I am currently on lockdown in California, I very much hate Trump but here is the thing. Just like the UK, the US has done nothing too little too late. Not every state is in lockdown, I am currently in a city with supposedly one of the toughest lockdown as it's the epicenter of a lot of the outbreak but this is a joke, people still go outside, everything is closed but people are just walking around, going to the same outdoor places to ''excercise/catch air'', the current system in the US means that probably as many people will die from the choice of keeping the lockdown going on too long as people will die from not having a lockdown in place. Unlike Europe, people cannot afford not to work here, uninsured people or even people with minimal coverage or even people with coverage (the average monthly health insurance cost here is 500$ per month for an adult) need money to afford their care (if they have other conditions or develop the disease), to afford their meds or even to afford their insurance as it would be a terrible time to default on payments. They also still need to pay rents and other necessities, and people who are most likely to get ill due to living in overcrowded multigenerational households with no health insurance are more often than not poor people who need to work and the economy to stay alive to survive. By stopping the economy indefinitely to save older people, you would ultimately help people like them starve, become homeless or die of pre-existing conditions/illnesses. There is no real help for poor people here (especially under Trump) and having kids or elderly dependent/cancer, doesn't protect you or really give you access to much help.
The UK is not the same and is lucky, but ultimately it's not as simple as stopping the economy to save the old and it having zero consequences on other people.
If you stop the economy for too long, lots of businesses won't recover, banks will go broke too, recession would be bad (and for the UK who is now out of Europe I don't even want to know what it would look like in terms of NHS or even quality of life for people).
Is the solution acting like the virus doesn't exist and re-opening everything? No. But killing the economy is also not a life-long solution. Maybe doing a reverse quarantine, keeping vulnerable people quarantined china-like until we find a cure while letting the others build an immunity? (Some people would still die of course but most hopefully wouldn't, though?) Not sure if that's feasible or how it would work, but right now I would argue that any solution can be an ideal solution. The goal ultimately is to save the most lives now while trying not to kill the economy so when this is over people can have, at least a tolerable quality of life to get back to.
Most of my family members have pre-existing conditions, and lots are over 60+, I get that they are high risk and that they depend on people and government measures to protect them. I would argue though that governments have been trying to throw them under the bus to save the economy as there would be no worldwide lockdown if elderly people were seen as disposable. The worldwide economy will already be on its knees when this is over, even if the lockdown is only a couple of weeks long. We are literally stopping the economy and putting everybody's life on pause to save them. We can argue whether or not it's enough, but I wouldn't say it's an orchestrated way to let old people die under our noses. Historically, if you look at wars and times of crisis, you will see that it's almost always young people (mostly fit men) who are sent abroad or to the frontline to be butchered, it's rarely (if ever) the elderly. And right now it's also the same, government are having to chose between sacrificing the future (as they could have pretended to) of the younger and healthy folks for the survival of the elders and disabled. I don't think it's wrong but let's not pretend it's as easy as a moral choice of economy vs death of the elderly as it's much more rooted than that.
As for the UK prime minister and how he has dealt with Corona, the idea that anyone had any faith in the government dealing with anything of major importancy adequately or effectively after the shit-show that was Brexit and genuinely expected them to be honest and factual about the situation (not thinking you did OP), is as laughable as anybody reading Trumps tweets as factual news. It was always going to be a shit-show and I feel sorry for UK people and the NHS who was already on its knees and probably won't cope with the outcome of the lack of decisions and delay in actions of the government.
The whole thing is entirely depressing tbh.