It's curious how many passengers think they know more about this subject than the airlines, and how many think it's all down to the 380 being comfier. The simple truth is that if the airlines decide the economics don't stack up, you will not have the choice of a 380 and will go on the cheaper 777.
As for criticising the 777X's comfort, that is plainly ridiculous - none of us know what it'll be like. There is a little difference between the later 777-300s and the 380, but it's not worlds apart. But the new 777s will have very different construction, which will likely reduce noise and allow a higher cabin pressure than the current model or the 380, and I understand that it'll have similar air humidification to the 787 (shame it won't have similar air sources, staying instead with bleed air). Given the nature ft he 787 and now the 73 Max cabins, I think it's fairly likely the 777X could be the more comfortable aircraft (if specced out the same way by the airline), but we'll have to wait to find out.
And I do agree with the comments about airport capacity/slots, though I hadn't really considered it before; I had though that crowded routes benefit, but the comments about extended wake separation are true and the overall number pf passenger movements correspondingly suffer.