I feel like I'm the exact opposite of what this article proposed however the entire thing confuses me.
I'm not rich but relatively well off, and, without doubt in the best financial position of my immediate group of friends.
If I happen to be the one that picks up the bill I often have people chasing me to pay me. I actually think that is a problem because they feel obliged to do the right thing, however I'm unmotivated because I don't care about the outcome -- I don't need the money. This is my fault and I feel poorly for it but the reality is that after I've had a nice evening I don't really care. In terms of the debt: honestly I probably wouldn't bother asking.
The very concept of asking someone for 4 bucks seems abhorrent to me. To be clear, I say this personally; I'm not struggling to pay rent/mortgage/utilities/whatever. If you're in a position where those are concerns then please absolutely follow up.
Chasing a $4 debt won't make you rich, ever. Even if you do it all the time. Anyone well off chasing this kind of cash is deluding themselves.
Generally speaking my friends and I operate over a long term fairness principle. "Bob got the last round, I'll get the next"; they won't be even but our assumption is that it'll balance in the long term. That applies to more than just the pub.