Ventilators are complicated, expensive machines. But there’s a simple design that doesn’t have a lot of moving parts and doesn’t even use electricity. Disposable gas operated ventilators might be mass produceable in a large enough volume to serve during the Covid19 surge.
In the US there is the Go2Vent from Vortran (more than meets the eye!). In India there is the SureVent, which is also for sale as an unbranded version by a unit of Bajaj Life Care. Strangely, the product sells for $90 in the US and approximately $270 in India.
If either of these companies could scale up production it would definitely help to cope with the surge. Alternatively, if an open-source group could reverse engineer these devices and release CAD files for a similar product it would allow distributed production of these devices by people with 3D printers. Definitely a promising approach!