The season 15 finale ended up being the lowest rating due to circumstances more than anything. They had to completely rewrite it due to Covid, the original plan was to a recreation of The Roadhouse (which they did) and have a massive reunion, have Kansas play Carry on Wayward Son and have a trip down nostalgia lane, unfortunately the last half the season had to be completely rewritten. It is what it is, but the issue with the finale wasn't just down to fatigue, there were lots of contributing factors