Jagex is looking for OSRS GP quick cash. Unregulated gambling in a game with addictive characteristics SoF is a perfect fit. Are you sure it's an investment that will last? It's not. Two reasons are why players will get sick of it and the law is behind, but will catch up when politicians understand that tax revenue is there to be earned. Japan experienced this recently. They were required to regulate their social games, which allowed for some gambling and they almost shut down most of the gaming companies. Because they didn’t focus on the games, but only the money.
Jagex could have asked the players questions about EoC. It would have given them dual wielding and the ability to use items such as drops or emotes, and then a slower growth. If it was even possible. Those things would have made for a happier place right now. Jagex refuses to listen to players' wishes. It's almost as if they don't have any control over what happens. In this case, the latest quest seems appropriate. The Brink of Extinction.
The economy is down because a lot of players have recently quit playing. This means there are a lot of items such as rocktails and sharks, ore bars, armour, and other resources. There's a lot of players playing the game, and they aren't buying enough of them. This is why the prices of the items mentioned have risen. This has caused many armour pieces to fall, but it will eventually balance out.
Runescape updates can be used to invest. This is the easiest way for you to get started. For example, with the introduction of the QBD or the new drops from KBD it is possible to expect anti-fire potions to increase, so you should buy a lot of those.
Ports owned by buy old school rs gold players might require the purchase of planks. Bolts and arrows could be investment options for the Dungeon that is a ranged-slayer. These are only a few an example of how you can benefit from these upgrades. You'll be able to comprehend graphs after some practice. While it may seem obvious to determine the best time to buy an item, or when it is the right time to dispose of it, it may take some practice to get it correct.