I believe most people do buy quality . . . .but it tends to be budget based. Most people buy the best quality they can afford. Unfortunately, some just can't afford as much as others, so they buy what they can if they feel confident that the tool will get the job done.
I still have my Thorsen socket and wrench set (Made in India) that I bought in high school in 1974. Are they quality tools? I thought so at the time, and have repaired quite a few autos with them over 30 years. Yes, I've stripped out a couple of the 12 pt. sockets, and broke the 9/16 wrench, but they seemed like pretty good quality until I could compare them to something better. Now the Thorsen set looks pretty poor by comparison.
So, the term "quality" is a moving target, based on what we can afford, and depending on what we compare it against. Knipex vs. other pliers is a fine example. Knipex are great. I own several pairs of their Cobras and their insulated electrical pliers. Are they higher quality than my comparable Channel Locks? I've got quite a few years of additional use on my Channel Locks and have never had a reliability issue. Still work every time, and that, to me, is an indication of quality. So I would have to say no, the Knipex are no better quality than my Channel Locks, but the Knipex feel better for certain applications.
As for your experience at Lowe's, it sounds pretty odd, but whatever. I don't tend to let tellers or others standing in line bear much weight on my decisions, but every once in awhile I'll learn something from the experience.
Dale