@alloutoffucks lots of people are in a similar situation but shutting down the country won't make you less vulnerable unless you isolate yourself.
People need to make their own decisions about keeping themselves safe. The government can't wave a magic wand, shut up shop for a fortnight and then reopen in 2, 3, 4 weeks and it all be over. Even if they did it's still a worldwide crisis not a UK one.
It's not something that has an answer and not something that anyone can control. You just have to calculate your risk on a personal basis and decide what to do from there.
You could chose to not work. The consequences will be you will lose your job, your home etc. The government shutting the country down will mean many people will not have a job or business to go back to and that choice is taken away from us.
Anyone can chose at this point to self isolate. For whatever reason. Forcing that choice on big parts of the country would be very foolish and cause more problems and still not stop the spread of the virus. It takes one person to infect another person, then another and another. What if they stop the UK from trading, bankrupt us then as soon as our borders open we get another case?
The country needs to be business as normal for as long as possible. How we going to pay for the NHS otherwise?