At the early stages of the disease there was strong evidence to suggest a 10 million+ worldwide death toll; ultimately it looks like it will peter out below 1 million, depending on how the USA and Brazil behave over the next 3 months.
If the death toll continued to increase, an open source ventilator designed to a minimum, fair standard (certainly not one of those 'bag-squeezing' machines) may have been worthwhile, IF it could be spun up quickly. But, I think ultimately, it would have been better to take an existing design and mass produce it. The secondary issue that no one seemed to mention is that nurses, doctors, etc are all trained on a set of specific machines that they'd find in their hospital. They may need to be retrained to use new equipment, which could take days. Existing equipment is also pre-certified and likely to be safe by design, or at least its limitations are understood.