In human terms, is not euthanasia a preferred and valid alternate to the artificial and selfish attitude of "life at all costs" now generally practiced?

I take it that you are talking about extreme and expensive technical measures to prolong life. These measures are of course artificial, but that in itself shouldn't count against them (what is wrong with, say, taking an 'artificial' pill for a headache rather than allowing the 'natural' pain to continue?). Is requesting those measures selfish? Well, we don't usually condemn as selfish those who spend resources even on comparatively trivial things -- such as CDs or cars. One's life is a condition for many if not all other goods, and most people believe that we have a right, other things being equal, to decide when it should end and in what way. Now it might be said that the resources being used to provide this kind of care could produce a whole lot more good elsewhere. But that point -- which seems to me a strong and important one -- applies to most expenditure, in the developed world at least, not to that on life-saving medicine in particular.