Because someone has to be "that one guy who brings up Payback every time because Payback actually had a couple of good ideas that were just overshadowed by the many downsides of being a 2017 EA game and having not one but two ungrateful militaristic fanbases":
..Fortune Valley had sections that allowed to do something like that..
..and Payback had a different playlist based on location and time of day.
The point I'm getting to is this: If Palm City (and I'm slightly annoyed several people have spoiled the fun I would've had everytime I'd say that name) is as big and varied as Fortune Valley (which, while we don't know yet, they certainly haven't made a big number of it thus far), I don't see why they couldn't repeat that trick, especially given that they've done away with the dynamic day/night transitions (that sounds awfully familiar) because.. reasons?
Or, you know, take a leaf out of literally every other open-world games book and make a few different "radio stations" (or just plain old playlists) for different tastes. Seriously though, why has it taken NFS this long to cotton on to this? GTA's been doing it for long enough for its first radio stations to be considered of legal drinking age in the vast majority of countries, so it's not exactly a new concept. Alternatively, regardless of how the soundtrack turns out, there's always the option of muting it and firing up *insert music streaming service/YouTube here*.
On a different note, not only is the supposed discovery of a Testarossa fitting on multiple levels (I'll give you a hint and say that one of them has no relation to Palm City being a Miami ripoff), it has also made me realise that this might just be the largest number of 70's, 80's and 90's sports- and supercars in an NFS game at launch since.. oh dear, one moment.. Testarossa, Countach, Diablo, 993, 930.. High Stakes? Not even the three Criterion-had-a-hand-in-this games come close to that number without DLC. There are definitely some conclusions to be jumped to based on this..
If all of this post comes true, bump the Hype-O-Meter to a solid 4. Let's see what the gameplay thingy they're supposedly releasing today has to offer.