Paying for rights to the space behind a seat may not be a great solution, but at least it's a solution, and debating about its merits may lead to a better one. The current situation is that there is no right answer: neither the seat-recliner nor the space-requester can be objectively said to be in the right, so who gets the space comes down to who is less polite and more assertive. If everyone agrees that whoever bought the ticket can claim the space or sell it to the person behind them, then that's an objective property right one can appeal to without having to just say "Well, I want the space, I don't care that you want it too, and I can be more of a jerk than you about it."
That's a good point. That said, I still take objection to the tone of the article. The author didn't motivate his solution in the way you just did; it was more of a "this is the obvious solution, and I don't really care about what other people say" approach. I'm fine considering this as a starting-off point, as long as everyone recognizes that having on-board reclining rights negotiations isn't really a long-term solution.
