So, the problem that THEN exists, is that if Mac only created the Guardian suit several yeaers ago, or only formed Alpha Flight less than seven years ago, then how did John Byrne write the series in the 80's?
To me, i don't know why some new comic book company (actually, DC could have stolen this idea for their re-launch) doesn't start out every issue of every series with a date ; the date the issue takes place in that company's continuity. All other issues and series would have to keep track of dates. Thus, as an example, if comic series A during issue 13 got involved in a battle that took place over two days, those days being the 5th and 6th of June 1991, then if series B anted to use a charcater from series A in a storyline (during the same publishing month) it would have to make sure that said storyline fit either before or after the two dates listed, and state so, or use a character that was free duing that time period.
In other words, screw the times/dates that we the readers read the comics at, and create your own times stamped right into the comics you produce and keep them the same always. You could start a series right now, having it take place in the 80's, you could state exactly what year(s) and date(s), and then there would NEVER be any of this confusion!