I have friends who can't get a wi fi signal in parts of their house, so they have multiple wifi networks.
As others have said, if you configure all your access points with the same SSID and password (and different frequencies, so they don't interfere with each other) client configuration is equally simple. And portable devices can roam from AP to AP as you move about the house (although I have noticed momentary interruption when the device switches AP.)
I am told (but haven't personally experienced) that if the APs support "Fast Roaming" (802.11r protocol), then these interruptions pretty much go away. Unfortunately, this isn't a common feature yet. As far as I know, neither eero nor Ubiquity support it yet. I'd love to know if the Linksys Velop does.
These mesh networks are meant to replace scenarios under which a repeater would've previously been used. ...
But there have been alternatives all along. In my home (similar scenario), I use HomePlugAV powerline adapters in three locations, each one attached to a Wi-Fi router (2 in bridge mode) to get Wi-Fi coverage for the entire home. It's not as nice as a mesh (because the three routers need to be configured individually), but you get most of the same benefits.
And how often do you think that happens in the average family home? Hint: almost never. Most people do nothing more than a bit of web surfing, some social networking, watch a little Netflix, and that's about it as far as their network use.
You've got a low opinion of users.
You don't need to be an IT professional to benefit from high LAN bandwidth. Printing over a LAN is pretty common, and pages with a lot of graphics do use a lot of bandwidth.
People also stream media (music, photos and sometimes even videos) from one computer to another (or to a phone or to an Apple TV.)
And even if everybody's traffic is strictly Internet-bound, very high speed internet access is not uncommon these days. I just got an ad from Verizon where an $80 triple play plan is sporting 150Mbps (and higher priced options going much higher.) You don't want a crippled Wi-Fi interfering when five different people want to all stream video at once to their respective devices.
The only proper way to setup a home is with multiple routers connected via Ethernet. Just run it through the attic, walls, or basement.
Ripping open walls and ceilings (especially if you've got a 2 story home with a basement) is far more than most people are willing to do for this.
Fortunately, there are wired networks that are almost as good (and are far better than Wi-Fi range extenders), including powerline networking and MoCA.
Of course, if your walls are already open (new construction, major renovation, etc.) then yes, definitely run Ethernet. It does work best, and if you're going to be opening and closing walls anyway, there's really no downside.
