You can't do that with every government service. You can't offer people a choice between police protection and its cash value, because police patrols tend to protect entire neighborhoods at once, not just specific individuals. You might not want to offer people a choice between a flu vaccine and its cash value, because you'd really prefer to have vaccinated neighbors. But critical life support isn't like that; the benefits are targeted to specific individuals. There's no reason those individuals shouldn't be allowed to choose different benefits if they want them.
Tirhas Habtegris would probably have taken the cash. Then she'd have gotten sick and regretted her decision. And then we as a society would have been in exactly the same position we were in last week—deciding whether to foot the bill to keep Ms. Habtegris alive a little longer.
At that point, there's a powerful human instinct to come to the rescue. Well, more precisely, there's a powerful human instinct to demand that someone else come to the rescue. (I'm guessing that in the wake of the Habtegiris case, nobody at the Daily Kos has taken to funding ventilator insurance for the poor.) Be that as it may, choices have to be made. A policy of helping everyone who needs a ventilator is a policy of spending less to help the same class of people in other ways. Accounting for "economic considerations" means—by definition—trying to give people what they'll value the most. In other words, economic considerations are the basis of true compassion.