(keep in mind this is a fairly exhaustive study of thousands of companies over 40+ years, not some link-baity blog)
Rule 2: Revenue before cost—that is, prioritize increasing revenue over reducing costs.
Now, there's a slight difference between "controlling expenses" and "reducing costs". But there's also a difference between "controlling expenses" and "making stupid decisions" and I think some of your examples are in the latter camp (as were Fab's).
If you have product-market fit and you can extract value, your focus should be on growing revenue. A couple $100/mo SaaS subscriptions, a corporate retreat, or buying employee lunches aren't going to make or break you. Unfortunately, as Fab confessed (in the article), they never found product-market fit ("we spent $200M and we have not proven our business model").
Playing with millions of other people's dollars™ makes it easy to forget this I suppose.