You are overlooking the secondary effect — what happens if you, a musician, a person who lives off having a positive public image, becomes known as the kind of musician who uses free market forces to effectively price fans out? Fans will not like it. It is not rational but nothing in music is. You win the pricing battle but lose the PR war. It's bad for your business and the entire business of concerts in the long run.
And with your particular pricing scheme, there is arguably still nothing stopping scalpers from scooping up the tickets after the price drops to a level likely to be profitable for them but before fans had the time to react. In fact it would probably benefit the scalpers even more because they will have more time to track price drops than your average fan!
What about both? Artists want money, fans want entry, reserve a portion for hardcore fans and the remainder by auction. Artists get to sell their $10k seats to the rich while looking like they’re giving an amazing discount to their fans.
This is a better idea, but you run into the problem of determining who are the more deserving fans, and you circle back to what Spotify is planning to do.
If you're selling out venues at 5x a normal ticket price you will quickly be playing in much larger venues until you can't sell them out except at face value
And with your particular pricing scheme, there is arguably still nothing stopping scalpers from scooping up the tickets after the price drops to a level likely to be profitable for them but before fans had the time to react. In fact it would probably benefit the scalpers even more because they will have more time to track price drops than your average fan!