Something I think is important also for songwriters to do in their sets is to include a 'trad' or 'trad tradition' song or two that fit within the set's parameters. It exposes the songs to an audience that may have little history with the genre.

Canadian students are infinitely more interested in Macdonald's
bar tabs than his speeches. But eventually they read his speeches even if only to find out why he drank so much. Here's Macdonald with the whole of the NWMP out looking for Riel and Macdonald gives him $50 to get out of Canada because frankly Riel's arrest would have caused problems Macdonald either didn't want to deal with or couldn't deal with. Why, just his shenannigans with the creation of the CPR are worth the trip to find out, because from that we got this nation.

So I mention his bar bills. And do a song now and then that introduces people to aspects of history with which they may not be familiar. Make it good and interesting and they'll tell their friends.

Of course, if trad is already your bag, then introducing newer songs that 'fit' the tradition certainly help convey the notion that music can be both static and growing at the same time.

And too, people need to know performers are listening to audiences. Audiences are filled with people who go to venues looking for something good. It's possible to give them something good and stretch the boundaries simultaneously. You will lose those who come with a narrow-minded view of what good means: "It's not the type of music I listen to." But with them you're often hooped before ya start, so don't worry about it.