[Newshound47]

If you look at the speech in its totality it's more about setting the stall for future policy and funding debate, possibly with an eye on a new government more favourable to the BBC.

In reality, I suspect that the BBC would be one of the last to switch off linear broadcast TV & radio.    There has been huge progress since the days of streaming a postage stamp size picture over dial-up with RealPlayer but it is yet to have the resilience and reach of broadcast, something Tim Davie acknowledges.  And let's not forget the BBC closed BBC3 as a linear broadcast channel, weakening itself in the process, only to bring it back.

My mother, who on receipt of a contactless debit card sent it back to her bank, still uses BBC Text - the BBC tried to close this down but had to withdraw due to opposition.

For some it is not simply a case of education, those with dementia for example may really struggle to adapt to a new system.

BBC one would surely be a strong contender to be the last traditionally broadcast linear channel left in the UK. 
Also another issue is internet failures are quite common. Most people with Sky or Cable have aerials as well so unless a power cut happens if one goes down they can still watch via the other. The Internet has gone down for me living in London a lot more than the power has in recent years. So being internet only cuts people of TV if it goes down unless they have very generous Data packages.