that's because of movement. Agassi was never the best mover. Give agassi pete's movement and pete wouldn't stand a chance against him from the baseline.
agassi's fh was wayyyy better on the slower courts, especially clay and better on other courts.
pete's fh had a little more top speed than agassi of mid-90s and later (young agassi had as much top level speed ) and was better on the run of course, but that's about it.
anyone who thinks sampras had much more pace than agassi on the fh is mistaken, it was only a bit more ....
I remembered we jousted back in the old days a few years ago. In other words, its no problem disagreeing with someone, but the over the top melodramatic stuff is extremely tiresome.
It doesn't matter, the key thing here is Sampras had the better movement, and due to that exposed Agassi's movement often, especially when he got the forehand into play, he put it into areas of the court Agassi couldn't reach.
By the way, what are these "other courts" you refer to? In that era I can only think of rebound ace and indoor carpet which is not used today, Sampras excelled on both. And what is extremely tiresome is this nonsense of fast courts and slow courts. Sampras was good on hardcourts, speed is irrelevant, we know he won in Australia, Indian Wells and Miami all slower surfaces even then.
Anyway we will agree to disagree, as far as I am concerned Sampras had the better forehand. Sampras copied the Lendl motto of camping out on the backhand side and getting either the inside out forehand or inside in forehand as often as possible. It takes a greater talent to do that succesfully than stand in the middle of the court and try to dictate play as Agassi did for many years.