it's already started to happen in Germany !
Lets be clear on what is happening in Germany. There are plans to start (note, start; afaik nothing has happened yet) to start switching off analogue terrestrial transmitters within the next year - no other forms of analogue television in Germany are under any immediate threat.
But, in Germany the broadcast situation is entirely different to the UK.
In the UK, analogue terrestrial is the bread and butter broadcasting standard. The majority of the country still uses it as their only method of TV reception. And amongst those with some form of digital TV, almost everyone still uses it to some extent, and despite 5 years of digital broadcasting some regional level services are only available this way (a situation which does not look about to change). Consequently, we necessarily have an extremely well developed analogue terrestrial transmitter network - 98% of the country is within range of an analogue transmitter. In the UK, analogue terrestrial is so common that it is classed as 'normal telly' with anything else still being seen an alternative addon.
In Germany, the situation is entirely different. The analogue terrestrial transmitter network was never built up to the same level - huge expanses of the country get zilch through an aerial. Analogue satellite is the way most people watch their TV - the reason you sometimes see the same things on different channels on Astra 1 is that most of the stations on there are actually part of a regional network (a true regional network too, not an excuse for one as ITV has become here) which is carried on satellite so that people can watch their local station - and that is how most people do it.
Phasing out analogue terrestrial in Germany is certainly the beginning of the end for analogue, but it's not going to have anything like the impact that ending it here soon would have. It's significant yes, but it's not going to effectively kill off analogue TV as it would here.
With the way the UK market is however, don't expect analogue terrestrial to disappear any time soon - I will be amazed if it's not still around 10 years from now.