Reforged is counting on WC3 veterans money. They arent going to bring in a huge WoW crowd, even though they are trying to appeal to them. This game is made for our money. They give us discounts they may as well lose money.
Warcraft IP is not at its height of popularity, it is shrinking. RTS is not height of popularity or even in resurgence, it is on life support across the entire genre. This game is made because classics are guaranteed sales and not a financial risk like a new IP could be (cough Immortal).
Reforged is like adding a new store mount in WoW but with a higher development cost. If they discount War3 players they may as well lower the price across the board.
If we want discounts, I suggest waiting for 2020 black friday. SCR is on sale right now and it came out last year.