Here in Sweden, your tax filings are public information; companies can just ask the government what you made last year. I have no idea if they actually do, though, and the data will be somewhat obfuscated if you have extra income on the side.
I assume such situations occur often in Sweden where it's really awkward if you want to hang out with a crowd from lower social class because they know your earnings.
You don't have to be in Sweden to have a pretty good idea within a few minutes of talking to someone, of what the ballpark for their earnings is.
Your social class is written all over your face, your clothes, your manners, your manner of speaking, the company you keep, the hobbies you have, where and how you spend your time...
This is not true for lots of software developers who grew up poor but got rich. I wear shitty clothes, live in the ghetto, my hobbies are video games, cycling, and porn, and when speaking I code-switch easily. If anything, it's the other way around - when I'm around city folks with their mannerisms and discussions about veganism I clearly see I don't fit and I come across as a neanderthal despite my income being around top 10%.
I moved out before finishing school (I did finish living on my own) and working 40 - 60 hours next to school - while being officially below the poverty line. This went on during most of my university days.
When starting a job I had to live frugally, because it had a really shitty salary.
Nowadays I am in the top 5 - 2 percent of earners (depending on how you calculate/count.
I still wear regular clothes most of the time. I nearly never eat out. I spend on things people do not really see.
So yeah - I can relate. Especially when being socially thrown together with the kind of people you describe. 100% second this.
Turns out, they were dead serious. For the rest of the evening we had some boring-ass shitty activities and insufferable conversations. 0/10 I checked out early and never showed up again.
It's not always too difficult to tell if someone is a software engineer from their behaviour and interests alone.
But yes, it's possible you are sufficiently outside the grain that you don't have any obvious tells about your social class. And, of course, a dedicated confidence man could fake enough of them to fool enough people enough of the time.
But that would be the exception that would prove the rule. And even if they were publicly available, you have to be deeply pathological to be looking up the tax records of your acquaintances, I can't expect that to be a regular problem in Sweden.
I save more than most and spend more on things like gear and vacation. Nobody knows unless I allow it to be known. Among my peers (coworkers and friends from places I've lived), I easily live in the area w the most poverty. I prefer to keep my income level private. If it were known, it would likely change the nature of my relationships. Worst would be the nonproft where I occasionally help the same ~20 people, most in awful financial situations.
So OP is - for eastern European standards (depending on which country specifically) very well off. Talking as if 100k€ was nothing special is actually quite telling imho.
Asset prices inflated so much that income is not completely irrelevant, but it is at best only half of the picture.
So no: Asset prices not necessarily always go up. It depends significantly on where you build/own and how that area develops over your lifetime.
But - this deferred gratification - paying a morgage now to pay less rent in the future is clearly a bet towards a future in retirement where one has less disposable income, so it makes - from my vantage point at least - sense to invest now to have more freedom later.
Others have freedom now - and need to potentially scale down later. Both are valid positions imho.
Edit: Typo
Interestingly enough I can't recall a single instance of a working-class person acting like this in a similar situation. A friendly ribbing and wise crack here and there, sure, but never as seething as somebody who feels like they should be making more than they do because they went to school for this, damnit!
to rephrase an old Chris Rock joke, "the worst thing to an enlightened college-educated person with a nickle is anyone else with a dime".