There are already play-offs for football's League Championship in some countries.
https://www.mlssoccer.com/news/playoffs-around-world-global-leagues-use-variety-different-formats-determine
I'm quite surprised at how convoluted some of these are, and if something similar to some of these happened in speedway I'm sure there would be howls of derision and cries of 'only in speedway'
...well apparently not.