I have many nerdy friends who have been Linux users for ages. But most of them don't know such a thing as Openwrt exists or have never bothered to give it a try. It's a very fun piece of software to play with and can be extremely useful for routing traffic. Wondering why it isn't more popular/widely used.
I've long known about it. I don't seriously use it, but I would if only my Wi-Fi router was fully supported. It's an Asus one (that I got for free from T-Mobile a decade ago) so I installed Asuswrt-Merlin on it instead.
Following the recommendation of homelab communities, I got into OpnSense (a BSD-based firewall system for x86 hardware only) last year, still keeping my Wi-Fi router as a dedicated AP. In hindsight I somewhat regret that choice and probably would've been better off buying a new OpenWRT-compatible router and using it to handle firewall/routing/AP all in one device instead of wasting the power draw of another separate N100 system. I like having wireguard and vnstat in my router now, which Merlin didn't offer, but I know OpenWRT has those too and I don't have any other needs that warrant a higher-power router.