The previous generation was the same. 4090 and 4080 really didn't have any competition either. And Nvidia priced the cards too high then too.
I don't see anything changing, though the 6090 might not gain as much as the 5090 unless they embrace better features or PSU makers start releasing PSU with 2 of the new high power cables on them... as then Nvidia could just keep feeding power in and causing fires all over the place.
Its not known what AMD might do next generation, all I knew was this wasn't going to push it very hard.