I think the concept has some value, but like most behavioral labels they’ve become so loosely defined and abused that they barely mean anything any more.

I can’t count how many people have chatted my ear off and bounced around the office, engaging other people in spontaneous enthusiastic conversation every day, only later to have them claim they’re introverted. The colloquial usage has expanded to encompass anyone who some times feels like staying home and watching Netflix instead of going out on Friday night. In other words, everyone.

I agree that it also becomes an excuse. I’ve had friends who really enjoy socializing and going to social events and also lament social isolation and loneliness, but being an “introvert” becomes the driving factor in their decision making about what to do on weekends or after work. You can see how much they enjoy social events when they’re basically obligated to attend (weddings, special event parties, immense peer pressure from friends trying to get them out of the house) but when left to their own decisions they’ll decide to stay home and be lazy 10 out of 10 times with “I’m an introvert” as the excuse. I’m excluding people with conditions like social anxiety disorder from this description, before anyone comments with whatabouts.

It gets really bad when they reach their 30s and 40s and they wonder why their friends have stopped sending invites to things (because they never accept) and they complain that dating is impossibly difficult (because they only leave the house for work)