The problem is, that all the skills that involve using the mixing window need harvestables - either directly like mixing essences, or indirectly like summoning. If harvestables get limited, alt-harvesting will be common as every harvest will be priceless. I won't be suprised if some people will try to trade between their alts to level up faster, forcing other players either to buy ingredients from such alt-harvesting players for very high price or to join the alt-harv competition. Also, if the recources get limited, their price will go up, and so will prices of the end products, like SRs and HEs. That might make training on mobs or even serping them non-profittable, and so the fighters will be forced to find another ways of making profit - as hauling will be no longer possible, they might be forced to harvest or even join the afk-harv society.
Another thing worth considering are new players. They are not wealthy, and lose a lot of ingredients until they develop their skills enough to start making gc out of it. With prices of harvestables going sky high, they might be simply unable to even start, and they might hake their character a pure warrior - and warriors need HEs, SRs and armor, which need harvestables, which are limited and dominated by alt-harvers selling them for high prices.