Your logic seems perfectly reasonable but unfortunately one bed apartments will only appeal to a single person or at a push, a couple - the family market wouldn't even consider it. Also, if a person was considering a move to city centre for an easier commute I think they would avoid a one bed and make sure they secured at least a two bed while they are forking out for stamp duty, solicitors fees, agents fees etc. Its an expensive time when you're moving house so trading up in bedrooms and space rather than down would be the main reason for moving as well as location. Sorry again to be the bearer of pessimistic news.
Just count yourself lucky, you have your own apartment in the city centre - that's alot more that most! Sit tight.