Here is a new post at EconLog in which Bryan Caplan discusses how signalling contributes to the status quo bias.
The lesson: In the real world, signaling naturally tends to ossify behavior - to lock in whatever the status quo happens to be. If you're an optimist, you can protest, "It's only a tendency." But even an optimist should admit that this tendency leads to atypically slow and unreliable progress.
On the other hand, someone who consistently dresses as a distinguished gentleman can do so in a jeans-and-T-shirt culture, if he actually is a distinguished gentleman. When the richest dudes around wear Crocs and bike shorts, it's just another way of expressing personality.
That said, the situation for women's clothing seems to be substantially more fraught, especially for engineers.
(And I expect it is different again in the game industry, which seems to have its own sort of presumptuousness.)