I was persuaded by a recruiter to wear a suit to interview the other day. It made me realise how lucky I am not to have to wear one every day. Seems slightly absurd to be required to wear a Victorian costume whilst writing 21st Century software.

Not a strange thought. Square shoulders. Hard lines. Dark colours. Not surprisingly it's sometimes referred to as modern armour.

This is a funny one and it reminds me of gold.

We tend to think of gold valuable because it is pretty, and because it's pretty we wear it, which gives it market value.

In reality, this is not untrue. But more importantly, we value gold because of scarcity, and that gives this not ugly looking metal value (there's not enough gold in the world for everyone, after all). And because it is valuable, we think of it as pretty and wear it, because it shows a certain status. This is why we somehow perceive fake gold so negatively, not because it's aesthetically different but because it's worthless. We hide this fact with words like one is 'authentic' and the other is not. While really, they look the same, and they're both arbitrary metals, but one is scarce and thus not cheaply available for all, while the other is.

In fact, quite some time ago aluminium shared the role of gold, it was even scarcer (before factories produced it) and more expensive. You can find anecdotal evidence of this, e.g. Napoleon holding a banquet where the most expensive cutlery was made of aluminium for the special guests, and the regular guests had to use mere golden spoons. All of that ended when producing aluminium in a factory was discovered and the price plummeted from hundreds of dollars per some unit (can't remember) to mere pennies. Today you'd look mostly foolish wearing an aluminium chain, mostly because it's simply way less scarce.

That's why I was reminded of it by your comment about suits. It's likely true that we consider suits to be serious because they're 1) uniforms and 2) simple, hard cuts

But at the same time, that's just today's fashion. In the early days of suits they were colourful, they had rounded shapes, they were also used as uniforms etc.

In other words, I think what actually makes them 'serious' is the people wearing them. You can find a garbageman uniform, or make one, that's cleaner and more modern and slicker than a suit. But we'd immediately attach negative connotations to that uniform. In the same way gold isn't necessarily the prettiest thing, but because of meta-reasons (e.g. it being expensive, or worn by cool people), it's desired. Suits are likely pretty similar. It's the fact that important people wear suits that inspires the seriousness.

Anyway, that's just one hypothesis of course :)

Fashion seems too changeable over time for that to be likely.