That's not an argument for letting this disease burn through our entire population. That's an argument for the government to step up and assist people during this time.
Edit: and who gives a shit about your retirement account.
People who for whatever reason are utterly dependent on support from the state might well give a shit about the state's decreased capacity to provide aid thanks to additional demand on the part of those whose retirement funds (which allowed them to be self-sufficient) have been destroyed.
At least in my country a big chunk of grandma and grandpa's retirement is subsidized by government programs, if not directly provided by government programs. The same way we provide disability coverage for people who end up out of work through no mistake of their own due to on-the-job injury, etc. You might have your own 401k you deposited salary into or have extra private disability insurance but a big chunk of your safety net here is a government program that you pay into while you're able-bodied and working and then draw out of when you're disabled and/or retired.
It's not as if a disease mitigation shutdown is the only thing that's going to crater grandpa's 401k. His stock holdings took a big hit during the 2008 crash too (as did mine).
Acting to preserve the economy first and foremost will not help those people. You have to keep them alive first while coming up with effective strategies to look after them later in the event that their retirement funds somehow evaporated. What good is protecting their retirement funds if the retiree isn't around to spend them?
Edit: and who gives a shit about your retirement account.