I think that one of the main driving factors is going to be sky lane congestion.
In Europe, getting a slot in and out is expensive. If you can lift more folks at a time, ultimately you will lower your costs.
Tn the USA, the two that have a big capacity problem (to my amateur knoweledge) are JFK and EWR. LAX and SFO probably do too.
Once the machines are in operation and the process for handling them is stable, I expect to see them being offerred at a discount. People may not want to go on the ultra big machine but te price will convince them. I think that Volume's example of the 747 is spot on.
As to Airbus marketing towards one area or another - they will be aiming it at ANYONE who wants to buy! They will offer ANY modifications they reasonably can, to sell it.
This machine may well be like the 747 - it will make or break the company. I am not a betting man, but I bet they will win.