It really would be nice if that were the case. Seriously. I wish I were able to explain it better as to why it's just not something that is going to be widely feasible.
Just to give you an idea: The nurse isn't just taking care of a critically ill patient like others. First of all, keep in mind that most of these patients have other medical problems (high blood pressure, diabetes, asthma, chronic lung disease, just to name a few). They have IVs in place with multiple medications that need to be given. These medications are coming from the pharmacy in the hospital. They have to be checked, drawn up, put into a pump, and given at the right dosage and the right rate. Same with IV fluids. Math and practical skills involved. Then all of these changes need to be done in a clean manner in order to not pass or introduce infection into the body that will overwhelm and kill them. Labs also need to be drawn. Patients need to be routinely turned so they don't get ulcers. The tubes helping them breathe also need to be constantly suctioned and checked without being dislodged. Vital signs need to be constantly checked to look for any small changes that could indicate a problem. Urine catheters need to be watched and then emptied. Then all of this needs to be charted so that it can followed. And then it all starts again. Because the blood pressure medication might need to be adjusted. Or the medicine to help increase the blood pressure. Or the insulin to help with the glucose from the labs that were just drawn. And then knowing enough to know something isn't right to alert the physician that they need to come and reevaluate and make changes.
There's a reason nursing school takes years and why critical care takes even longer to learn.
None of this has anything to do with a ventilator itself.