Have any further info there you can share?It's always hard to predict but I think F-150 is particularly vulnerable right now against the triple threat of Chevy/GMC/RAM which are all outstanding catch-ups to the Ford. Ford's SuperDuty business however is probably stronger and closer to a refresh to coincide with the arrival of more Medium Duty competition.
F-150 is just much farther away from a new design so it's going to be the old kid on the block for a number of years so presumably that will either come with better deals or fewer sales. I think GM's Full-Size truck business has a chance of overtaking Ford once again in the interim but I doubt one brand will overtake it.
Either way, Ford has some outstanding new Trucks coming to widen that gap again and to match some of the nicer amenities of the new guys.