Ethereum will become more scarce after the implementation of the first phase of the Casper FFG upgrade, which will take place in the summer and autumn of this year and will combine the mechanisms of consensus PoW and PoS.
Casper FFG will reduce the award of PoW-miners from 3 ETH to 0.6 ETH, and the funds will be distributed among users by the PoS method. The total award of PoS- and PoW-miners will be 0.82 ETH per block, which will reduce inflation to 2%. After the update is implemented, the annual volume of emissions will be 2 million ETH.
As you know, in 2020 in the bitcoin network there will be a halving of the award for the block, which will also reduce the annual inflation rate of BTC to 2%. Thus, Ethereum will reach the same index a little earlier than the current market leader.