I’m pretty sure a lot of it is simply because that sort of mixing style is pretty fashionable at the moment. If you mix movies like they were mixed in the 90s and 2000’s (i.e. very clear and distinct dialog) then they don’t ‘sound’ modern.

Even in cinemas the mix is awful and almost inaudible half the time. Extreme example but I saw Tenet at the cinema and had to guess at half of the dialog because Christopher Nolan is especially and increasingly fond of this.