and it’s not even gonna introduce a new audience considering the original is in HD ported to every modern console

It definitely is going to introduce a new audience to this game, there are people that won't touch the original because it doesn't play as fluidly as the newer games (tank controls + no walking and aiming). What most of them don't realize is that the original RE4 was the game that revolutionized the industry because it was the first title to feature the over the shoulder camera and gameplay.

Also statistically speaking RE4 is probably the most loved game of the franchise worldwide. Does it need a remake like 2 and 3 did? definitely not, but people who have played the original back in the day will throw money at the remake because what capcom's shown so far is a fantastic modern rendition of the original, and everyone's a sucker for nostalgia (and capcom likes money if it wasn't clear lol)