There's sort of two components to this problem. There's the human
behavior component, which is a super tough nut to crack. And then
there is the institutional component; among the most common complaints
about Wikipedia are its bureaucracy and the complexity of
contributing. Solving the institutional, systems issue is complex...
but a lot easier than getting people to act nicer. Take a look at the
newest dispute noticeboard WP:DRN, or even arbitration enforcement, or
SPI, etc. These are unimaginably complex for people new to Wikipedia,
and only the starkest examples of a problem that also afflicts
articles and article talkpages.