It seems like every 5-10 years or new development points to wearable electronics. First, transistors, then microchips, a decade or so ago, it was small lithium batteries, now? compact wireless. Of course i didn't RTFM, but we've been "wearing" our electronics for years. Carrying cell phones has been the status quo for a decade, walkmans/diskmans for longer. Yes, we carry more electronics every day, but I still wear a timex ironman which has the same functionality as the timex ironman I got in 1994 (indiglo FTW!). However, I doubt that people will consent to wearing t-shirts that monitor heart rate, undies that take/analyze stool/urine samples, and shoes that measure stress as long as you can get cheap clothes that look good and are comfortable. Also, the average person can, you know, feel what's going on with themselves and if they're the kind of person who would buy a watch to monitor heart rate, they can take their pulse by hand and will. How many people do you know regularly check their pulse? Especially when not exercising?
Wearable electronics are in direct competition with simple sensors that feed into your smartphone. Integrate the electronics into a garment and you only get to wear it once a week (more if you're grody) or however often you do laundry. Watches do lots, but people like not having to recharge or change batteries more than once a year.