I see where you're coming from, and as much as I understand it the problem is we don't have osrs numbers. We don't have 100k people playing the game every single day, skilling supplies are usually in low demand (unless ofc we're talking about things like herblore/smithing supplies). Also because it's so easy to max out an account and it take so little in terms of supplies to attain those levels resources aren't needed as much. (For example it probably takes around 1000 sapphires from the shop to get 99 crafting) where as in osrs that number would be somewhere around 130k xD)
So unfortunately there's a giant gap for skillers here because people either pvm or pvp. What I'd recommend is to either try some high level pvm content, or give pking a try. If neither of those sound appealing, break the boundaries! Start your own skilling team, if you notice an item that has 0 supply and it's in insane demand (coal,addy bars, herblore supplies) take control of it. Dominate a monopoly and reap the rewards of your efforts.
Anyways, Good luck regardless and if you need any help in game or someone to play with hmu!
Ign - Shruggy