Bitcoin is blockchain 1.0 and limited Supply = 21M BTC (now about 17M mined)
Etherium is blockchain 2.0 with another mining algo (for GPUs not ASICs), programmable language (solidity), smart-contracts but unlimited Supply (now about 100M ETH mined). ETH's developres are planning to upgrade it to Casper Protocol with POS-POW mining in near future.
The supply of ETH actually is limited. As the white paper explains, the rate of supply production will eventually reach 0, thus making more supply impossible.