I buy dark roasts from a local coffee roaster in my city. They don’t have any fruit or floral notes, but they taste like dark chocolate, not burnt rubber. They’re good dark roasts. Starbucks is still crap. It only tastes good in a giant cup of milk and sugar and caramel sauce.

That wasn't about dark roasts, that was about Starbucks' coffee and roast. There's a big difference. Starbucks goes darker than most specialty roasters' dark roasts.

Also, "burnt rubber" notes often come from robusta coffee. Robusta is cheap, easy to grow, and has a long shelf life. The darker it's roasted, the less it tastes like burnt rubber[^1]. But Starbucks claims that they use 100% arabica. If true, then it's almost impressive that they made it taste like that.

[^1]: There are some amazing, exceptional robustas, but you won't find them in commodity coffee or Starbucks