@vriley You are omitting a lot of information in the world or wireless. Bonded channels, having Wireless-G device on a Wireless-N or Wireless-AC network, distance, obstruction, EMF, and tons of other factors can effect speeds. Wireless-G 2.4 GHz maxes out at 54 Mbps, yes, but that is an antiquated standard that is very rarely used in first-world countries anymore. Wireless-N uses multi-channel connections to offer up to 150 Mbps on 2.4 GHz or 600 Mbps on 5 GHz. Wireless-AC offers over 1 Gbps on 5 GHz. Again, as you say, that's in a perfect scenario, which never happens. Realistically, AC sees speeds around 100 Mbps.
Another major flaw in many older routers or router/modem combos is the processing power. Many people I know would frequently experience slow speeds or even intermittent disconnections on WiFi. When I inquired into it more, I discovered that these people had 10+ devices all connected. Older routers were designed before the IoT age, when you might have had 3 computers connected at maximum. Now, between computers, tablets, smartphones, Smart TVs, game consoles, appliances, light bulbs, garage door openers, door locks, security systems (w/ WiFi cameras)... (the list goes on) you need more processing power in the router to juggle all of those connections.
@thundervore Arris makes Surfboards... They bought the segment of Motorola responsible for home networking in 2012. Not sure how long ago it was that you were "smart enough to demand" a DOCSIS 3.0 modem, as they were made standard almost a decade ago. Almost every Cable ISP around has been requiring D3 modems since 2010-2012. Technology world moves fast... The way you are talking is like talking about SPI like it was just phased in favor of SAS last month. Cablevision requires a D3 modem for the Ultra 50 service, meaning you probably sounded like a dummy and/or rude for "demanding" a modem they would give you anyway.
Source:
http://optimum.custhelp.com/app/answers/detail/a_id/1791/kw/DOCSIS/session/L3RpbWUvMTQ1MDI4NjgzMS9zaWQvdmpQWXY3RW0%3D