Something that you won't see is, for example, Lufthansa, switching all it's AB
) (FRA / FRF / EDDF), Germany">FRA-NYC flights operating on 747s to A380s - what you will see is those services that today have a high load switched to the A380 to offer even more capacity.
Will the A380 eliminate services to smaller cities? No, it won't - why should it? Passenger numbers are growing again, and there are services today where the only capacity adding would be possible by adding yet another flight in a very tight timeframe (there are Europe-Asia services where you can see 4 or more 747s departing within 2-3 hours), or adding flights with schedules that the passengers do not want (for example daytime flights from Europe to South Africa - several airlines have tried, but passenger numbers went down drastically enough that most, if not all, have gone back to night flights).
It will be a trickle-down-effect - services that today manage to fill one or more B744s per day will eventually be upgraded to A380s, while services that today manage to fill one or more B777s or A340s per day will move up to B744s... and so on.
The additional capacity by the A380s is not being introduced in bulk, that is all currently ordered planes in one day - but over a timeframe of several years.
If routes "survived" being upgraded from B767s to B777s or from B777s to B747s without a serious reduction in frequency, then why should the upgrade from B747s to A380s now suddenly constitute a situation that warrants a (more or less drastic) reduction in frequencies?