I think 3.5 inches is the minimal for me. At least 4 inches
The recent GB bespoke Russell only happy to do a 3.5 inches.....
I have no jacket with lapels wider than 2.5" but whether something is fashionable or not doesn't worry me in the slightest. You can wear whatever you want provided you get the look right e.g. You wouldn't wear narrow lapels with flared trousers, well you could but you'd just look daft. Getting the balance right is an artform in itself.
+1 on the gorges - I like my lapels at about the same level is my tie knot.