It's not about being tough and macho. A lingering decline can be psychologically painful for everyone involved. Pretty much everyone I know that has been involved in caring for someone who suffered a slow decline - particularly alzheimers - don't want to go through that themselves.
You say now that you may want all the tubing and to be bounced around from doctor to doctor (not all of whom know what they're doing, by the way), but it's a very different beast when you're actually experiencing it. Some folks just say 'do what you gotta do'. Others say 'I don't care what you think you'll find with yet another test, the endless battery of tests is worse than the disease'.