Whither the DT fly line?

[tailingloop]

I help operate a fly shop. No surprise to us that DT lines seem to becoming more scarce. We sell 20+ WF lines for every DT. Very few customers ask for a DT line and most that do are in their mid 50's or older. I'm in the shop one day a week, Saturday. I think I have only spooled 2 DT lines for customers in the last 6 months. A few customers have picked them up to spool themselves.