Not sure I understand the logic in that statement. And in my experience, it has never been a scam. It used to be included and now one must pay on certain ticket classes. But that does not mean it's a scam.

I pay for a seat 100% of the time when it is not included in the fare and I consider that expense when making the purchase. I want a window or aisle as far up as possible and ideally with more legroom.