Actually if you have phone thru cable, the situation is the same. If the cable tv is down, etcetc. same with landline. And almost all of us has a mobile phone.
Otherwise if the internet is down, that is breaking of the contract. All service providers has to agree for a period of time, after which you don't pay for the period. But in this case you have to report immediately that the net is down otherwise the time is not registered.
I have net with wifi for more than 6 years and had no problems with it.
