Repair costs and other sinks are not relative, and the money already exists, if it's not changing hands you don't have an economy.It kind of depends how aggressively prices drop and if they scale across the board. Prices are relative. Even if you don't make as much money selling, if prices are down everywhere, you also don't need 40m for Enthusiastic anymore. It was the same case when rare drops like S2 mats plummeted. Yeah you only got 1m for a Lakoria Fang, but you only needed like 10m for a lvl 80 weapon as opposed to 100m.
Price drops are a double edged sword. If everything is cheap, what the hell will you sell for money? I imagine if "the rate of enchantment failure was greatly reduced. = needing less scrolls to finish enchanting, price is going to dip pretty hard, pretty fast.
Not to mention usually when a primary resource drops, a secondary resource is inflated to compensate, such as the case of "trash" drops being worth more when the rare materials are more common. In this case, it's likely Magic Powders and Elixirs would have some inflation.