Agreed. Major ISPs in the US (and I presume many other places) offer routers that work well enough to satisfy the requirements of any non-technical household and often come with provisioning/troubleshooting features that enable the ISP to provide technical support if necessary.
In the old days, ISP-provided devices often lagged behind other consumer or prosumer network offerings, and it made sense to swap them out... but that's not really the case today. Today, swapping out the ISPs router is probably going to make a non-technical user's life harder, unless they have someone technical to manage it for them.
Satisfaction happens when a product or service meets the user's requirements. A new Cisco catalyst setup may be technologically superior to my mother's ISP provided router, but it might not make it easier for her to play Candy Crush on her iPhone if she forgets the wifi password.
I mean, when the first thing you hear when you call your ISP, is to "reboot your router" on a recorded message, doesn't that throw a red flag to anybody else? I don't use high end gear at home like Cisco, either, but it has never needed a reboot.
This is symmetric gigabit product, but still.
I'm not familiar with that device, but a non-technical user might not care about that "problem", as long as their device does the task they are intending to perform.
I am sure that AT&T's CPE equipment is lackluster, but that doesn't mean it won't work to do basic tasks to the satisfaction of a home user.
I can tell you from experience that large downloads and uploads cause latency-sensitive applications to stutter in a way that is fixed by using ubiquiti gear.
In your defense, you did say non-technical household, but I dunno -- I don't think that wanting to use, eg, backblaze for backup and not have that tank zoom makes you a technical household.
I actually run OPNSense for myself at home, but for my parents I deployed full Unifi. This way if there's any problem, I can remotely look at the network in the cloud console and try and see what's wrong.