I don't know what kind of machines you used in 1985, but 80x25 was easily done on an A1000, and was what you were competing against on the PC side in most instances.
There were many problems for Commodore, but lagging on the graphics side vs. the PC was not an issue until years later.
He said non-interlaced. You had to buy (an expensive after market) scan doubler to get rid of the flicker on the Amiga. Biggest mistake they made .. they should have included a true workstation class high resolution mono video mode.
Doing productivity apps on the Amiga in its highest resolution vs the Atari in its highest (monochrome) was no comparison.
The Atari did better in certain markets -- MIDI sequencing, big time, and to a much lesser extant DTP -- because of this.
But having that nice mono screen for productivity didn't make the ST a big success, so I don't think the original comment stands.
The Amiga was not a success because it wasn't an IBM PC.
If the A1000 had managed an 80-column non-interlaced mode, it might have done better initially, but as it was, the machine was a joke for business.