1-2 years, perhaps.
As I understand it, to instruct at PPL level you will no longer be required to have passed the CPL or ATPL exams, you will not be required to hold a Class 1 medical - and EASA intends to file a variance from ICAO in allowing PPL/FIs to instruct for remuneration.
However, there will still be experience requirements to meet and the FIC to pass - no chnages in instructional standards will be accepted.
This should allow more experienced PPL holders to become part-time FIs and reduce the industry's dependence on pre-airline hours builders.