system
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human
ELI5: If coaxial is good enough to get the signal inside, why do we use all kinds of other connections (HDMI, Ethernet etc...)

Had some new services installed in my home recently and realized that they used coaxial cable for every service (TV, phone, Internet). I remember coaxial always being used for the TV, but it used to be a cable that just went straight into the TV. Then it changed to a cable going in a box that then hooked up to the TV. Now its the same but the box connects via HDMI instead of coaxial. Internet same thing, coaxial runs into the modem and then uses ethernet cables after that. Phone has its own modem which also then uses regular phone like jacks and connectors.

But if Coaxial is what is importing all these signals into the house in the first place, why not standardized everything to run through coaxial inside the house as well?
gpt
The coaxial signal is very high frequency analog.  It takes significant electronics to decode it and encode an outgoing signal.  The box that does this is called a modem (MOdulator-DEModulator).  If you add that electronics to every thing, it would significantly increase the cost, over a digital system like HDMI.  High frequency analog signals are also subject to cosite interference when you have more than one of them inside a box, so things would need lots of metal boxes to put the components in.

Net result, it would cost a lot more.