i would agree with alphamale.
Changing shiny encounter rate so drastically would be a bad idea for the economy.
The value of Shinys have been relatively solid in the past three years,it is like gold in the real life.people can jump into shinys to shift risks when the value of currency (whether it is eggs in before or now pokeyen) is fluctuating.
but tbh if such encounter rate keep going.i doubt if the economy would be destoryed.Its just our shiny trader and mostly collectors would be drastically influenced.Cuz 5*encounter rate means our wealth would be less than 1/5 in before.
Anyway in the pokemmo communism the wealth of minority havent been actually respected in most of those updates,so if shit happens i wont be so surpurise,maybe its just our time comes.