Note that openwrt has a big community of contributors and not all devices/features are supported. In contrast the manufacturer firmware is at least feature complete and easy for regular users to set up.
OpenWrt is also free. Both as free software, and free of cost. When you're paying a manufacturer for a product, surely it's not too much to expect them to ship with functional software that also happens to be up-to-date and secure?
You can get that, but not at consumer-grade router prices. I have a separate router that I put behind my stand-alone cable modem. I paid for that separate router about $200.00. And another $100 for the modem. A wifi access point cost me another $100.
So it's about $400.00 for a router that has updated firmware(pfSense). Or you can cheap out and spend only $100.00. This is what you get by doing that.