It could be done as a time travel storyline, an isolated area like NI's Ancient Greece. No weapons created after 2005-06 is allowed, no enhancers, no SIB, no other recent features. Also can't take anything back with you. ...
Have u visited the old noob area, Port Atlantis - Othros West Mound - Billys Spaceship Afterworld triangle recently?
Exarosaur was a decent hunting mob once, there was team hunts on the bigger ones. Now it has become harmless like fly - if they become too annoying it's a one shot kill. Small Daikibas, that have become Shinkibas now, same.
There was a Cornundacauda spawn N from PA swamp camp. These were so strong a noob pretty quickly learned to leave them alone... U could travel further N up to "Atrox belt", that was the natural border that only ubers could pass. Going east there was Atrax area, those had nasty big aggro range and damage to be taken serioulsy - if more than 1-2 attacked at once u were in trouble... and the occasional wandering Gokibusagi further east near Billy's Spaceship was a certain death.
The today's "middle class"
(= not noobs any more, not ubers either) has close to 200 HP and 30-40 Evade. Means, big part of the old world would be no challenge.
Back then we dreamed about growing up and over time we did that, some more some less... Now we trapped, we can't really go back there any more. Would be like walking in some odd museum, but nothing to do there.
Main problem is our skills. So yeah, for this to work, definitely
can't take anything back with you. Including skills.
If this requirement is followed, the same old economy would work the same way as now. Well at least no big difference anyway. The question is, would we really agree to these terms? Back then we didn't know about the big bad nasty mobs of the future, now we would have to sacrifice it all.
OK, suppose upon entering there's some temporary skill-debuff, say, 75% of all your skills will be removed - and when u return from the past u get it all back... then it might even work. Up to and including full days of hunting with no deposits.
Next problem, if this
Old-PE-world becomes too popular, it might kill the economy on the "mainland"...