I got one in 1982 at 22 because I traveled to Europe to visit my DH when he was active Navy. I went to Italy at 22 and France at 24. Before that I had never imagined I would need a passport. Fast forward to 2005 when we started cruising and I had let my original expire so I had to start the process all over. So, now I'm on my third passport, and will be getting my fourth. Growing up, the only "foreign" travel anyone in my family had done was driving to Mexico where you didn't need a passport and my great uncle who served in Guam during WWII where he only needed his orders. When I was growing up, I thought only wealthy people had passports because no one we knew traveled overseas or cruised. Now, everyone I know has been out of the country (my generation of siblings, our sons, cousins, nieces and nephews). My parents are 85 and have only been to Mex and Canada. Never say never.
My feeling also is that if you can afford to spent $1,000 or more on a cruise, you can afford to spend $120 on a passport. How many of those saying they don't want to spend the money on a passport are spending $1000 and up on drink packages?