During times of economic turmoil, such Keynesian economic proposals get busted out, left, right and centre. Unsurprising really: John Maynard Keynes formulated his ideas precisely to respond to this sort of event, to protect workers via the state where private enterprise would not. This is better for the workers than simply letting the invisible hand of the free market decide their outcome, but ultimately based on the same capitalist mindset.
Keynes's ideas weren't enacted so workers could eat: the policies just ensured they could buy and consume
Keynes’ intention was never to help the working class per se, but to provide a way for capital to lift itself out of crisis. His centrist policies aren’t enacted so workers can eat, but so they can buy and consume and provide the demand for that all-so-important supply. This is same today: we can see the lack of care for working class people in the failure to provide universal healthcare in the US (which resulted in the death of a 17 year old boy with corona, who was turned away due to lack of insurance), or in the failure to provide personal protective equipment (PPE) to medical staff after profiteerers bought it all up.
Keynesian economic thinking did not prove to be a permanent shift left after World War II: it resulted in neoliberalism. Soft left policy simply placates workers, whilst appeasing capitalists who continue to exploit more and more until another crisis occurs. A certain bearded philosopher, famous for his critique of political economy, predicted this cycle of crises and the inutility of the soft left over 100 years ago. Coronavirus and the response to it is revealing his predictions to be true, and perhaps reveals a break in the capitalist realism that would posit capitalism as the only working system we can have.
No establishment part is willing to provide a permanent shift to the left
A permanent move left requires a break from capitalism itself if it seeks to be truly effective. No establishment party is going to provide this, least of all the right, which dominates global politics. What is needed is a realisation amongst people that there is in fact an alternative. Basically, read some Marx.
Elisabetta Pulcini's article outlining how coronavirus could change politics is available here.