Towards the end of your post you said "Everything must be overwhelming and draining for them."
As someone who grew up being labelled as painfully shy but finally diagnosed with anxiety over a year ago (and recently told I come under the social anxiety umbrella), I can tell you that EVERYTHING is totally overwhelming and draining. I even had an anxiety attack in my therapy session today - a safe place where I should feel completely safe - but I can't even manage that.
Anxiety is an irrational, terrible disease that can be crippling. For me it is on top of depression which I was diagnosed with many years ago. Simple, everyday tasks like getting dressed and cooking are anxiety inducing, going out always results in an anxiety attack, no matter how many techniques I use to try to help. I would rather never go out, never meet anyone, never get out of bed, but unfortunately I have to. It was so bad recently I tried to commit suicide and at one point I was detained for my own safety. There is no way I could have just got on with life, there was no way I could have been rational at the time, the only way I got through those days was with other people helping me, I could not have done it myself.
So far in the last few months I have tried 3 different anti-depressants, they only take the edge off the depression and anxiety, the second one stopped helping and sent me into a downward spiral which resulted in the worst couple of months of my life, hence I am on a third one now. My therapy is, hopefully, going to help, but there is no explanation for why I have some of the anxiety. I have been 'on sick' for a year now and I have no idea when I will be fit for work.
I really don't want to feel this way, I try to just get on with things and on good days I can, but at other times it is literally impossible to. Life is hard, anxiety is tiring and terrifying at times.
I hope this small snapshot of my experience helps you understand a bit better. There is a difference between being a bit anxious, it happens to everyone, and full-on anxiety, and so many people nowadays think they have anxiety, but they may only have the normal, day-to-day thing.