I've been into HF operations for only about six weeks now, but I have faithfully mailed out paper QSL cards to every contact I have made (other than the W1AW stations I've worked), It makes over 40 QSL cards I have sent off. My response? Only five have returned the favor. From looking at ham operator profiles on QRZ it seems that many hams only respond by electronic QSL card, others demand an SASE (sad, I think, that a ham who can afford to spend $15,000 on equipment is unable to afford a roll of stamps), and others say outright that they don't QSL at all.
Is QSLing a thing of the past? I wish now that I hadn't bought so many cards from the printer....
Yes and No. QSLing today as far as paper QSLs is done usually with and SASE if you want a card. Postage cost too much today for many hams to QSL. The reason they can afford equipment is because they are not spending money on postage.
Many are now doing electronic QSL. There is LoTW and eQSL. I use only LoTW because it is the only means accepted for real awards like WAS, DXCC, and VUCC. The eQSL awards are cheap looking and not from a recognized ham radio group (my opinion, others will differ I'm sure).
I spite of what some claim, LoTW is easy to set-up. Some think the security is overdone, but in this day and age, you can never have too much security with systems.
So I have over 5,000 QSO records in LoTW and over 2,500 QSLs. The postage alone to get those QSLs would have been over $1,000 dollars. Using LoTW, I have several WAS and DXCC awards (different endorsements).
So paper QSLs are fun and attractive - I still do paper for those who want them, I much prefer LoTW to earn awards.