Just to clear things up: since the last update, every untradable item that would be dropped in PK, is alched and dropped as cash instead. So no, you can no longer pick up untradables from wilderness.
Also, wipe wouldn't benefit the economy. It would just turn back time and happen all over again. Yes it's partly our fault by allowing to recover accounts from Emps-Scape, but even without that the combat levelling is very quick, which means that high-level content would be available fairly fast. Look at Jp for example: he maxed an ironman within 2 months, with just the combat and slayer it's even quicker.
So no, bank wipes and account resets wouldn't fix it. It's just a temporary solution, which would piss off most players and make them quit.