iceman and other NW guys will remember the analysis that they put out on the DC-10-30 replacement back around 2000 or 2001.
They compared the 767, 330, and 777. The 767 didn't carry enough cargo like a real widebody (tsquare just fainted
), the 777-200 was too much airplane, and the 330 carries just about what the 777-200 does at a fraction of the cost. You've pretty much got to have a route that requires a 772 to justify that added cost.
Strap some new motors and a more refined wing on there with the 330NEO and you've got even more of an advantage.
I don't think we'll be able to get around ordering the 777-300ER for the first whale parkings, though.... and with the offering of the 777X now, the price for the 300ER will drop.
So, my bet is for around 30 330NEOs and 10ish 773ERs.
The 789 is a possibility but not much of one, and I'm not thinking the 350 will be a factor for a bit.