I agree.
Chrysler had the most aggressive advertising, and really focused on their racing efforts. Unfortunately, it didn't translate into massive sales, they had some really cool ads, and some incredible cars.
The Olds 442 was definately the most serious threat to the GTO early on. The 442's biggest advantage over the GTO was in handling department, as all 442's used a rear sway. Over at Pontiac, John DeLorean felt a rear sway bar would hurt the ride quality of their cars, so all through the 1960's, right up to and including the 1969 models of the Trans Am, Grand Prix, and Judge, were without a rear sway bar. When DeLorean left Pontiac in mid-model year 1969, the engineers started putting rear sway bars on the all the high perf 1970 Pontiacs.
The 442 went unoticed the first two years (1964-1965). It wasn't until 1966 that a special package (W-30) became available, in extremely limited numbers. It seems as though Olds was struggling to find out what kind of performance package they wanted to present. The tri-power 1966 442 was a definite image builder, but they still couldn't get the word out to the street crowd when SS396's, GTO's, Hemi's, and GTX's were dominating the stoplight drags. Even in the old road tests of the 1966-1967 era, the magazine writers had to sort of apologize for running a test on an Oldsmobile, because they simply weren't very popular with the young people. Oldsmobile seemed to get a handle on things in 1968, and really pushed the whole "Youthmobile" and "Youngmobile" attitude in their auto show displays and magazine ads. Again, this was why I stated that before 1968, Oldsmobile knew they were fighting their own stodgy image. In 1968, they changed directions and went with a whole youth theme, more miniskirts, and more go-go boots.