If people continue to buy looms at such an outrageous price, then the price will rise. Simply common sense. If I retire one gen and sell my loom point for 600k, then see others are successful selling theirs for 700k. When I retire next why would I sell mine for any less than that?
You want to stop the rise of loom point prices? Stop buying them. That person selling it for some absurd price will start lowering the price until it sells. Many people see playing after 31 as a waste of time, so they won't hold onto it for long.
Most likely, some people won't care about it and continue buying loom points. Prices will increase, people will continue playing. Looms aren't necessary to be effective, they are just nice. This is what happens when we have nice things =D.