Very interesting.
I heared this rumor before but from another theory. Since 80% has been mined, the computer miners will work longer and harder in order to “print” new bitcoins. The thing is that you have the “halving” factor which cause the reward to be with lower value.
The harder and longer mining- the lower reward.
This will cause to all the mining companies to close thier businesses since they are not profitable anymore, which will cause for lower  and lower demand. This will impact the market and the value of the crypto currencies will drop off. 

All i wrote is a ccording a rumor that i heared from one of the analysts on my country.
Would love to know your opinion about it.