Many employers that have been 'closed' will realise they need to adapt. First they need to think about how the can ensure social distancing and how many people they think will need and can accommodate. They may not need everyone yet if business is going to be low. They need to think about PPE requirements, catering facilities. Then they need to think about commuting issues- car park spaces, can some not work from home- and also those with child care issues while schools are shut.
A good employer will allow and encourage home working where possible, call some staff in when the time is right , keep some furloughed if possible and allow holidays or unpaid leave for others. There may also be a mix of part time work and full time work, coupled with any furlough flexibility that is being considered in this area.
Employers should adapt and the better ones will. The government can't be expected to sort everything out for them. And employees need to be flexible too- maybe take some holidays or work from home if asked, for example.