Look, Wi-Fi still kind of sucks. And marketing excesses aside, its worst problems all revolve around airtime distribution among multiple devices.
Unlike LTE (the protocol cellular data uses), 802.11 WI-Fi is a protocol with no central management, which leaves all nearby devices duking it out for airtime like angry, unsupervised toddlers. There’s only so much you can do to fix this problem without radically overhauling and replacing 802.11 itself—but as new 802.11 protocols emerge, they do their best.
A brief overview of the alphabet soup
If you don’t deal with this stuff for a living, it’s easy to get lost in all the different Wi-Fi protocols in the ether today. New additions have been released in sort of alphabetical order, but some are backwards-compatible and some aren’t. Some are “mainstream” and have broad consumer device support, and some are offshoot technologies rarely to be seen in anything you can buy at a big box store. It’s kind of a mess.