People like this have ended the learning phase of their lives. Learning is hard. Why learn new things when you can just bullshit the answer using the knowledge that you already have? This is the classic move of the know-it-all, and we see it happen time and time again.
I think this sentence is emblematic, in my opinion you stop learning when you stop breathing, anyone who doesn't understand this is as if they have already stopped breathing.
The world changes and evolves, every day there is something new to learn but, as you rightly say, you can't teach an old dog new tricks.
I really liked your post, and besides being interesting you made me smile he he!
Thank you!