Not only in the US, and not only because of being "highly paid" but "spending too much".

In most of the world, including large parts of western Europe, unless you're upper middle class and higher, it's either hand-to-mouth or smallish savings (nowhere near 30%).

Which parts of western Europe?

I see via google that minimum wage in Germany is 1473 euros per month for a full time worker.

According to [1], food, housing, necessary household items, and public transportation look like they could reasonably total less than 800 euros per person. Add another 100 for having fun and for the occasional wardrobe expense, and you still get to save nearly 40%.

Having children ruins all of this, of course, but that's pretty easy to avoid.

[1] https://www.expatistan.com/cost-of-living/berlin

Germans save around 9 to 11% of their disposable income, of which the average (post taxes) amount is around 25-30.000. This puts their annual savings to around $2200 to $3300.

That's nowhere near being able to save 30-40% of your pay, as the parent said. And Germans are some of the biggest savers in Europe. For places like France, crisis stricken "PIIGS" (Italy, Spain, Portugal, Greece etc) and especially the UK it's even worse.

There's a large difference between being able to and choosing to save that much. I didn't say that it was the norm, but it's certainly possible if you have a near-median salary. Not doing so is a choice if you make a reasonably good salary, albeit an extremely common one that most people don't make consciously. It requires consciously tracking your spending, and being willing to forgo or at least cut back on some of the luxuries that have become much more common in the US and presumably Europe in the past 30 years (like eating out frequently). In return, you can get better financial security, even without an astronomical salary.