The ferry service to Mui Wo will cease to exist in early November, it has been run on a reduced schedule (only 2 sailings per day on weekdays) since August already.
As for your observation that we 'rarely venture outside' - it isn't exactly quite like that. Most DB residents venture outside quite a bit - like adults commuting to work or the kids that don't go to DBIS or Discovery College, commuting to school.
I do find your generalisations interesting though