The way I see it, there are four factors that makes the classic runner mage fairly unusual:
1) scope of magic. As said above, some of the 1% may not have achieved noticeable abilities, some are physical adepts, some are aspected.
2) power of magic. I tend to assume that amongst those 1% awakened, distribution of base magic is similar to any other attribute. In other words, most awakened have a magic of about 3 if they haven't put in a lot of effort to improve it. (Granted that most would have had good incentive to do so)
3) Traditions and mentor spirits. Some people may be flexible in what tradition they follow, or what totem they relate to .... but some people are strongly pulled in a specific way, and more have only limited flexibility. Some will never find instructions in a tradition that is meaningful to them (part of why the 1% are not all active), some will follow a tradition or mentor spirit that doesn't work so well in a corporate setting, or in some cases with people in general.
4) General competence as a mage. There will be some with low willpower, or called to shamanic magic but with low charisma. Or their personality makes them poor at studying and learning certain skills, including magical ones (a hermetic mage with severe dyslexia may learn skills and spells more slowly).
Unfortunately in first edition, there was one sort of magical character in the core rules: magic 6, access to all magic skills.(although not as powerful as current magicians), and of course most players would set skills and attributes to maximize their magical effectiveness. So it set as the norm the most extraordinary case.
I think where the lawyer comparison doesn't work is that tbere are many people who could be lawyers, and only a select portion of them are allowed to become lawyers, so that those who do are generally fairly talented in that regard, and reasonably likely to stay as lawyers. It might be better to look at the tallest 1% of the population and look at how good they are at basketball, or something like that.
