In college we referred to this same idea (among my peers who were going on through graduate studies, particularly PhDs) as "academic incest", where you aren't sufficiently exposed to a diverse enough set of ideas and end up too narrowly focused or clouded in your judgment.
Ways to overcome it include: moving (in academics, accepting a fellowship at other institutions; as a professional, change jobs); observation (keeping abreast of the latest trends outside your immediate environment and field); community participation (attending conferences, symposia, and similar things; or even forums like this).
But ultimately it requires a recognition that your views, knowledge, and beliefs are, necessarily, constrained by your experiences and that you sometimes have to seek out novel experiences or the experiences of others to change yourself. If you lack the drive for either, or too great a confidence in your own present state, then you're going to be stuck.
There will be things they do so well they aren't even on your radar, and you will have a huge blindspot there. And there are things they tolerate that pretty much nobody else will. So you will either suffer in ignorance or learn some nasty, nasty habits.
Without moving you see no diversity, and without seeing diversity you shouldn't be put in charge of building anything for 'everyone'. You are only qualified for niche solutions, which unfortunately outsiders might not clue in on until they've invested heavily in your ideas.