Because he was not outplayed by Brown, unless you are measuring Brown's full season against 6 games for Metcalf before he injured his neck.
He isn't exactly a straight line threat either. He is explosive coming out or his breaks with excellent footwork. Ole Miss never had him run a very detailed route tree (just like A&M with Reynolds) but he has a well oiled frame and should have no issues running any route. It doesn't hurt CBs have to respect his vertical speed and that allows him extra cushion. Or that press coverage is in-effective in slowing him down off the line because of his brute strength.
He is:
A vertical threat
A YAC threat
A redzone threat
A good blocker in the run game
The Rams still need a redzone threat, McVay loves vertical speed (see Cooks, Brandon) and loves guys that can operate in space with the ball (he's a monster with his hands on the ball).
So yeah, I think McVay likes Metcalf. That said, he will not be there.
Don't waste your time looking back, you're not going that way. - Ragnar Lothbrok