I mean… it’s certainly possible my games have been much more combat heavy than the norm, but it seems to me that Con is among the top 3 stats for pretty much every build, not just "some popular builds"…
Combat is just one of the three pillars but it’s also the one you die in


…
You don’t die from failing an Insight… unless you fail to sense that the cup of tea you’re being handed is poisoned (and you dumped Con so you’re failing the save for it). You could miss an important clue from failing a social challenge, or be inconvenienced (land in prison, etc) but rarely is it fatal.
For the exploration pillar, it’s a similar story. You may get stuck if you fail, but your life would rarely be in danger, and if a trap you failed to disarm does put you in danger, that’s probably a symptom that you lack HP and therefore lack Con
Con is rarely the first stat but even more rarely is it the last.
I did play a character with like 3 in Con once in the name of concept, but I knew full well I was dialing up the difficulty to 11. It definitely was not because it didn’t matter, optimization-wise.