Semi-technical history and discussion (all technical terminology
   linked):

     When wireless networking based around the 802.11b standard first hit
     consumer markets in the late nineties, it looked pretty good on
     paper. Promising "11 Mbps" compared to original wired Ethernet's 10
     Mbps, a reasonable person might have thought 802.11b was actually
     faster than 10Mbps wired Ethernet connections. It was a while before
     I was exposed to wireless networking—smartphones weren't a thing
     yet, and laptops were still hideously expensive, underpowered, and
     overweight. I was already rocking Fast Ethernet (100 Mbps) wired
     networks in all my clients' offices and my own house, so the idea of
     cutting my speed by 90 percent really didn't appeal.
     In the early 2000s, things started to change. Laptops got smaller,
     lighter, and cheaper—and they had Wi-Fi built in right from the
     factory. Small businesses started eyeballing the "11Mbps" that
     802.11b promised and deciding that 10Mbps had been enough for them
     in their last building, so why not just go wireless in the new one?
     My first real exposure to Wi-Fi was in dealing with the aftermath of
     that decision, and it didn't make for a good first impression. Turns
     out that "11Mbps" was the maximum physical layer bit rate, not a
     speed at which you could ever expect your actual data to flow from
     one machine to another. In practice, it wasn't a whole lot better
     than dial-up Internet—in speed or reliability. In real life, if you
     had your devices close enough to each other and to the access point,
     about the best you could reasonably expect was 1 Mbps—about 125
     KB/sec. It only got worse from there—if you had ten PCs all trying
     to access a server, you could cut that 125 KB/sec down to 12.5
     KB/sec for each one of them.

     Image: D-Link's DI-514 802.11b router. It was a perfectly cromulent
     router for its time... but those were dark days, friend, dark days
     indeed.

     Just as everybody got used to the idea that 802.11b sucked, 802.11g
     came along. Promising 54 screaming Mbps, 802.11g was still only half
     the speed of Fast Ethernet, but five times faster than original
     Ethernet! Right? Well, no. Just like 802.11b, the advertised speed
     was really the maximum physical layer data rate, not anything you
     could ever expect to see on a progress bar. And also like 802.11b,
     your best case scenario tended to be about a tenth of that—5 Mbps or
     so—and you'd be splitting that 5 Mbps or so among all the computers
     on the network, not getting it for each one of them like you would
     with a switched network.
     802.11n was introduced to the consumer public around 2010, promising
     six hundred Mbps. Wow! Okay, so it's not as fast as the gigabit
     wired Ethernet that just started getting affordable around the same
     time, but six times faster than wired Fast Ethernet, right? Once
     again, a reasonable real-life expectation was around a tenth of
     that. Maybe. On a good day. To a single device...

   In full >
   [1]https://arstechnica.com/information-technology/2017/03/802-eleventy-
   what-a-deep-dive-into-why-wi-fi-kind-of-sucks/

References

   1. https://arstechnica.com/information-technology/2017/03/802-eleventy-what-a-deep-dive-into-why-wi-fi-kind-of-sucks/