This is the problematic assumption.
In a currency with a fixed percentage of inflation, the demand has to increase forever in order to keep the price steady or rising, which is not possible on a large timescale.
Though I recently didn't followed DNotes and I think it is still PoW only coin, what can you tell about it as example for steady growth? Of course it is nearly impossible to preddict what will happen in 1-3 or even 10 years, but I think that every coin who has active development and community has a good chance for steady rise in price.
Very little. Are you trying to link the presence of inflation as the source of steady growth? If not, why try to link the two?