That only works if you actually have the ability to fill the aircraft, smaller WB/UWB aircraft are cheaper to maintain, require less crew (even per passenger), consume less fuel and are much less restrictive in terms of airports in which they can land and be serviced.
People don't count the fact that one of the reasons why smaller jets are more successful these days is that airports became much better at air traffic control, planes land and take off much faster on average than even few decades ago, combine it with more airports being built or expanded into multi-runway airports and you got much more landing/takeoff slots than before.
Big planes take quite a bit of space in the airport, they need special taxi considerations, and special terminals (especially the A380 with it's full double deck design), all of which comes with a premium in airport taxes when operating such aircraft. It would not surprise me if landing a single A380 costs more than double what landing a A330/787/777 costs these days.
And since It's not only cheaper to fly more smaller planes to the same destination, but also more commercially appealing to customers I highly doubt that companies will continue to run big ass planes for much longer, yes the A380 won't go away, neither will the 747-800 but i really doubt they'll get much more beyond the original orders, and even most of those I'll suspect will be converted into cargo within the next 10-15 years.
I flew on the A380 and the 787-800 to HK (Lufthansa and BA), and on a 777/787 on the same route, and I have to say the smaller aircraft are much nicer to fly on, fewer people, quieter, you get more personal service from the staff, bathrooms don't look (nor smell) like a porta potti at a Kiss reunion concert after the first 3-4 hours of the flight.