We are a tertiary resource. If two Wikipedians used different sources to arrive at the same place it makes no difference in the way that it would for a secondary source. Your argument is just strange. It seems to make the specific source more important than the information itself.
I'm not making my point very well, sorry. I'll try again:
*Citing* reliable sources isn't very important. What is important is *using* reliable sources. When someone writes something from memory and doesn't cite a source, the problem isn't that they haven't cited a source, the problem is that they didn't use one.
Citing sources is just the easiest way to confirm that reliable sources were used, it's not the important factor, it's just the way we confirm the important factor.
Someone writing an article and expecting someone else to find the sources is wasting their time, as the person finding the sources will be doing all the work. The actual writing of an article is generally the easy part, it's finding the information with is difficult. The wiki concept is great at copyediting and making things easier to read, and that's the only bit a writer that doesn't cite sources does.
Perhaps we should encourage people to start articles with just bullet point facts and let the people that don't like research take over from there. (Obviously, if someone wants to write the whole thing, no-one will stop them, but we should make it clear that just doing the research is useful work that can be done independently of the writing.)