Probably for the same reasons that programmers don't - for all but the simplest of procedures there may be unforseen complications, particularly since they mostly deal with legacy "applications"
Of course there can be unforeseen complications, but those are the exception rather than the rule. You can also have complications when you bring your car to the mechanic. Still we want to know what a typical oil refill is going to cost, and if it's going to be more expensive than expected we'd like to know what the damage is going to be so we can make an informed decision.
I don't buy that we can't handle the truth and need to be shielded from the pricing and costs structure of medical procedures. Especially because most medical procedures are purely routine matters and the hospital can just publish the average cost of those procedures. You'll then at least get a rough impression of what the price is going to be and you'll be able to compare hospitals based on that.
Should we[1] be shopping around for doctors? Hire a doctor like you would a Web Developer, what are your prices, experience, show me some of the stuff you've done before, etc. This is typically done with cosmetic surgery but should be we doing it with required but not emergency situations?
[1] when i say "we" i mean you Americans, i'm in the UK and have the NHS
* Her cardiologist. He did a _great_ job of heart surgery after her heart attack, but she wasn't thrilled about the way he ran his clinic on her follow-up visits. So she got another guy. That this guy was closer to the house is an unexpected bonus.
* Her orthopedic surgeon. Visited several guys when it came time to replace her knees. Picked one she liked who is also uber-competent.
Digression: Ten years ago when this guy was a middle-aged doctor knee replacements were a hand-crafted affair. Now the doctor runs the operation but a kind of CNC machine does the actual cutting, uses lasers to measure things and customize the new knees.
CNC machines cutting new knees: it's an awesome century so far.
