I kinda agree with you, tbh. Tho I’d apply that logic to more than just difficulty.
That said tho, I’d also be okay with the devs putting the most work into normal mode but also tossing in barely tested, unbalanced easy and hard modes with a “this is not the intended experience, use at your own peril” warning. I know no AAA dev would do that but I’d honestly be okay with it.