This sounds like what cheap OSRS gold I imagined OSRS to be when I first heard about it This design philosophy is modeled around the 2006 Golden Era of Runescape, the most popular and balanced version that I have really fond memories of.
It's like the polar opposite of the current game. I don't believe the OSRS team is willing to make these drastic changes to an already bloated economy, it would be very tough to make it appeal to the community. That's why it deserves its own server.
As a secondary server with few worlds it would be easy to notice botters. Jagex would have to place extra emphasis on bot detection in this area since it would impact the game more. You would think no real person would mine pure essence.
They just let it be. Before GWD there wasn't a single gold grateful monster that dropped magic seeds in the game. Magic seeds were super expensive! How great was it when you were woodcutting and you pulled a magic seed, that made your week.