It's not going to be "we will need to be locked down for 4-5 years"
But I've been reading a lot of public health experts, economists, etc... and it's likely the disease will be with us for a long time, and it's going to completely change how we interact as a society. I don't doubt we will find ways to engage on socialization and economic activity again in the relatively near future once we get it rather under control. But it's going to wreck anything requiring the gathering of a significant number of people in one place for a while.
https://www.theatlantic.com/health/archive/2020/03/how-will-coronavirus-end/608719/
This is the best article I've read on how this probably looks longterm issues. It's likely going to be multiple, repeated lockdowns. School closures will be a regular part of life and we should plan to get resources available for distance learning. Things like national availability of broadband internet and chromebooks for kids, for instance, could become very important. Mass gatherings may be able to happen in the periods where there are no reported cases, but cases will pop up repeatedly and threaten to reignite the blaze.
It's going to be a very tough next few years.