*Looks at the homepage of vgchartz* Yep, they still compete with each other.
Your arguments againt are not very convincing. The music analogy doesn't work. If you were talking about 2 specific games that have different audiences, then I could get behind it. It doesn't work well because both systems offer a range of overlapping games and genres.
Overlapping users doesn't mean there isn't competition. If a game comes out on the Switch I want to play that means I'm spending time and/or money on it, and not the ps5.
The form factor of these systems is irrelevant.