How much longer should we expect DIP (or DIL) Packaging to be around?
I haven't used a DIP component in 15 years. Even for 1-off hacks I would prefer smd stuff. Whenever I see a DIP part I can't help but shake my head. Unfortunately, there are still lots of companies using DIPs. That's why they are still made. Even so, few if any if the new stuff us made in DIP.

DIP parts will probably be around for another 10+ years, slowly getting phased out. That's my best guess. The 555 in DIP will probably outlive all of us.