If they continue to serve excellent tasting beer, they can make all the profit they want.
Incidentally some of the best beer service I've received recently has been at places like Port St Beer House, Sparrow Bier Cafe, and North Bar - that you might deem "trendy". If that means they actually play good music, and serve bites to eat, I'm all for trying to be trendy by you know, appeasing your customers.
But some of the worst service has been in renowned "real ale bars" where being under 30 seems to put you immediately to the back of the queue.